Tuesday, February 12, 2019
The Donald MacDonald 1828 Collection
I've started playing again through the Donald MacDonald 1828 collection. It's the earliest significant collection of light music I've heard of, and other than his earlier collection (which is mostly ceòl mòr), the first fully ornamented.
And boy, howdy, some of the ornaments different. Most are the same as are played now, but there are ones that have dropped out of use since then. Here are some things I'm finding in just the first three tunes:
Many of the patterns we know are present, like the g-d-e-d grace note rule. But when the figure involves the low-hand only, such as in the "A Highland Reel" bar 4 and "Sweet Molly" bars 3 & 7, the d-grace note might be used to start a bar, in the way the g-grace note is used for both high- and low-hand transitions today; and it sets up a d-e sequence. When this pattern is interrupted, as in coming from high g in the last bar of "A Highland Reel" (which prevents the d-grace from being executed), I have a hard time not playing it instead of the e-grace that's supposed to be there.
Also, crossing noises are used as ornaments! In Highland music! Specifically, a transition from d to e in "Sweet Molly" bar 11 and between c and e "Sleepy Maggie" bars 2, 4, 6, and 8. There's a low A grace note between them, and the only way to execute that is to forcibly allow a crossing noise when changing from the low to the high hand note.
I'm seeing Leumluaths and grips used in place of melody notes; the first A in "Sweet Molly", for example, but also in bar 11, there's a sequence of f melody, low g grace, d melody, low A grace, e melody. The only reasonable way to interpret this is a melodic sequence of f-leumluath-e-f, with the leumluath taking a full eighth note's worth of time. I think that's why what normally would be the grace note in the middle of the leumluath, the d, is here notated as a melody note: musical accounting. That time has to be written somewhere.
Also, interestingly, light half-shakes on d (ie, using a c echo beat) are common, even from notes other than high a or high g. Sleepy Maggie's B-part is full of them.
There's a lot to unpack in this collection, and I'm going to have fun doing it.
And boy, howdy, some of the ornaments different. Most are the same as are played now, but there are ones that have dropped out of use since then. Here are some things I'm finding in just the first three tunes:
Many of the patterns we know are present, like the g-d-e-d grace note rule. But when the figure involves the low-hand only, such as in the "A Highland Reel" bar 4 and "Sweet Molly" bars 3 & 7, the d-grace note might be used to start a bar, in the way the g-grace note is used for both high- and low-hand transitions today; and it sets up a d-e sequence. When this pattern is interrupted, as in coming from high g in the last bar of "A Highland Reel" (which prevents the d-grace from being executed), I have a hard time not playing it instead of the e-grace that's supposed to be there.
Also, crossing noises are used as ornaments! In Highland music! Specifically, a transition from d to e in "Sweet Molly" bar 11 and between c and e "Sleepy Maggie" bars 2, 4, 6, and 8. There's a low A grace note between them, and the only way to execute that is to forcibly allow a crossing noise when changing from the low to the high hand note.
I'm seeing Leumluaths and grips used in place of melody notes; the first A in "Sweet Molly", for example, but also in bar 11, there's a sequence of f melody, low g grace, d melody, low A grace, e melody. The only reasonable way to interpret this is a melodic sequence of f-leumluath-e-f, with the leumluath taking a full eighth note's worth of time. I think that's why what normally would be the grace note in the middle of the leumluath, the d, is here notated as a melody note: musical accounting. That time has to be written somewhere.
Also, interestingly, light half-shakes on d (ie, using a c echo beat) are common, even from notes other than high a or high g. Sleepy Maggie's B-part is full of them.
There's a lot to unpack in this collection, and I'm going to have fun doing it.
Thoughts on being a "Celtic" musician.
In recent months, I have begun to have increasing misgivings about using the word "Celtic" to describe the music I play.
Granted, I will not stop doing it - I can't. The term is too deeply ingrained in the imaginations of my potential audiences and clients for me to ditch it. But, more and more, I'm realizing that the term is simply wrong.
To explain why, I have to explain what a "Celt" is.
In modern parlance, the cheeky response is: "A Celt is anyone whose culture is invited to be represented at the Festival Interceltique de Lorient", the huge annual Celtic festival in Brittany. But in more serious terms, the term describes the peoples of the British Isles - excluding the English, but including the Norse-influenced Scots-speakers of Shetlands and Orkney, the lowland Scots themselves, and sometimes the Northumbrians - and their culture; and extended to include the people of Brittany, whether they are Breton- or French-speaking. More recently, this modern definition has been extended to Galicia and Asturias, and it seems to be broadening still. It's only a matter of time before the Basques are admitted as bona fide "Celts".
A more accurate functional definition would appear to be "any ethnic minority indigenous to the Atlantic coast of Europe (excluding most of the North Sea), but including the Irish."
Indeed, the "minority culture" seems to be the main purpose of describing Galicia as "Celtic", to distinguish themselves from other groups in Spain. Certainly there hasn't been an imported Celtic language spoken there since the 9th century AD, when the British colony of Britonnia was reabsorbed into the local population, and no indigenous Celtic language since the last centuries BC, when the region Romanized. When you ask "Why is Galicia 'Celtic'?", you get answers like "We play bagpipes, love to drink and dance, and are superstitious!", which - besides being offensive - would apply equally to almost every rural culture through Europe, regardless of language family, whether Celtic, Germanic, Slavic, or Romance.
With the Scots, Shetlanders, and Orcadians, the reasoning simply seems to be, they live in a country once dominated by Celtic speakers (Gaels), and thus the whole country and all its inhabitants are "Celtic". The same goes for Ulster Scots and the majority of Irish who don't have a functional command of the Irish language. I suppose this also applies to the ethnic English who, because of historic waves of immigration, dominate much of Wales, but not their neighbors in England proper.
By contrast, in historical parlance, a Celt is one of the three broad "nations" of ancient Gaul, along with the Aquitani and Belgae, centered in what is now south-central France. There was an additional group self-identifying in Roman times as "Celtiberians", who claimed to be a blending of Gaulish Celts and the peoples of Iberia. Though the ancient writers did sometimes, especially early on, when contact with them was limited, lump all Gauls under the blanket term "Celt", by the Roman era, they distinguished the Celts from other Gauls - and they always made a strict distinction between Celts or Gauls and the peoples of Britannia and Hibernia. Though some writers described certain tribes of Belgae as living on the south coast of Britannia (and archaeology finds evidence of their towns, or oppidae, there), this only means that the English channel was not a hard border for the Belgae; but at no point does an ancient writer describe a Briton as a "Celt", or had Celts living in Britain (again, because they saw the Belgae as a distinct group of Gauls from the Celts).
So why do we equate the two? Why do we imagine a unified thing called "Celticness" that somehow spans across time and distinct ideological and material cultures?
The story starts with the Scotsman George Buchanan (1508-1582), who, along with the Englishman William Camden (1551-1623), identified linguistic similarities between the contemporary indigenous languages of Britain and elements of the classical place names of the Gaulish peoples living on the European continent, and hypothesized that the Gaels and Gauls might have descended from the same people. This line of reasoning was further developed by the Breton Paul-Yves Pezron (1639-1706) and the Welshman Edward Lluyd (1660-1709), and eventually "educated" people from the British Isles came to draw a direct line of lineage from the Celts of Roman Gaul to the peoples on the fringe of Britain and the northwestern coast of France. A "mania" for all things "Celtic" swept Britain, especially English-speaking elites, tying them to the glories of Rome's greatest foe in the west, and people opined freely about the connections between the continent and the British Isles, desperate to reconstruct the religion, belief, material culture, dress, and the like of the "ancient Celts" to bolster their own identity as English-speaking, but not-English. This mania was, not surprisingly, not shared by actual speakers of what had come to be called "Celtic" languages.
Archaeology bought into this hook, line, and sinker, and quickly the Urnfeld, Hallstatt, and La Tene cultures were immediately identified as Celts, and despite only superficial borrowings of those archaeological culture packages turning up in an insular context, were grafted wholesale in the public imagination onto the islands of Britain and Ireland.
Linguistics did its part. Seeing all the related languages of the Continental Celts and the Britons and Gaels as one fairly close family, it split them not according to grammatical features, but according to whether the Indo-European "k" sound was rendered as a "k", or as a "p". While the Gaels and the Celtiberians used a "k", the Britons and Gauls used "p", and this was used to show that the Celts were once a united "race" (and oh, yes, 19th century notions of race were a big part of this), and that the Britons and Gauls drifted away and innovated relative to the more primitive Gaels and Celtiberians, and spread out from their presumed Alpine homeland in two waves just before entering the historical record.
Nationalism played a role. By claiming that Gaelic had its ancestry in Gaulish, Anglicized Scottish Gael elites, desperate to prove themselves worthy and loyal parts of the British Empire, were able to distance themselves from rebellious Ireland by claiming linguistic descent not from Old Irish, but from the heroic Vercingetorix of Classical lore.
[Oddly enough, the Picts were often excluded from Celtomania. Without the slightest shred of evidence, and despite the fact that Pictish personal and place names are clearly very similar to Old Welsh, the Picts were often assigned "Teutonic", or even "non-Indo-european" status, possibly to assuage the anti-Gaelic nationalism of Scots on the east coast, but certainly because the more a sense of mystery could be contrived around them, the more mystique they accumulated to themselves, and to their then largely Scots-speaking descendants. Indeed, to this day, you'd think "almost nothing is known about the Picts", as if they vanish without a trace at the end of the era of Roman Britain, when in fact they were discussed extensively by Bede and the Annals of Ulster and the Book of Deer, having ongoing relations with both Gael, British, and Northumbrian cultures on their borders.]
But Celtomania was always built on the shakiest of foundations. The cracks should have been visible from the beginning - the same Classical sources mined and extrapolated from in order to create the myth of the Celts also made it clear that the Britons were not Celts, though some tribes of the Belgae appear to have had outposts and towns on the southern coast of Britain. The archaeological cultures associated with the Celts largely never turned up in Britain or Ireland, not for want of searching, except in the form of imported goods.
Linguistics casts significant doubt on the unity of the continental and insular "Celts". The much-vaunted "k/p" shift turns out to be trivial, with numerous examples of it turning up in a range of language families - and this breaks the purported link between Celtiberian and Goidelic on the one hand, and Gaulish and Brythonic on the other. More significantly, the insular Celtic languages, whether they be Goidelic or Brythonic, share major and important innovations absent in the continental languages: the verb-first word order, the mutation of initial consonants, and the pervasive amalgamations of pronouns with prepositions. Some analyses of lexical changes place the break between the insular and continental branches as far back as 3200 BCE +- 1500 years (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC166441/).
Whole-genome DNA studies have been recently casting further doubt. Throughout Europe, the indigenous Neolithic peoples appear to have suffered a major population crash concurrent with the arrival of the Bronze age, with a mere tithe of the genome north of the Mediterranean coast descending from the Neolithic farmers (and fewer still from the Paleolithic hunter-gatherers before them). Most of the region dominated by the "Celts", insular and continental, is dominated by genes from a new population that arose in the Eurasian steppe, likely associated with speakers of Indo-European languages. That much jibes with the myth of the united Celt - but these same studies find little admixture of the Bronze-age populations that settled Britain and the Continent since the time they have occupied these regions - since ~2800 BCE, until the later migrations of historical times (such as the arrival of Anglo-Saxons and then Scandinavians in Britain).
This means that the Continental Celts and Insular "Celts" were very likely as linguistically and genetically isolated from one another as they were with other, non-Celtic, cultures well before the dawn of the Urnfeld culture on the continent, and possibly older than the Bell Beaker culture that preceded it. Furthermore, the break between the Continental and Insular "Celts" could potentially date to early in the expansion from the Eurasian Steppe itself, before arriving in Britain and Western Europe.
The presence of "P-Celts" in Brittany, once part of Gaul, it turns out, is a far more recent affair - these are the descendants of British immigrants in the 5th century, integrated into where large numbers of Britons serving in the Roman Legions had been settled when the legions were withdrawn from Britain itself a century before, and immigration continued in response to the Anglo-Saxon expansion in their homeland in the 6th century. They were not the descendants of Gauls, as earlier writers like Pezron had supposed, but are as much insular "Celts" as their neighbors in Cornwall.
What, then did the Insular "Celts", or rather Britons, and Continental Celts have in common by the time historical sources encounter them? Well, other than languages slightly less distantly related than their common ancestor with other IE language families, not a lot that isn't of a level similar to linguistically less related neighboring groups.
When you think of "Celtic" religion, what do you think of? Okay, Druids. And - I hear some of you reminding me - Caesar assures us that the Druids of Gaul, who were interpreted as a mix of scholars and clerics (akin, perhaps, to the the role of Brahmin in India) were sent to Britain for training. We don't know much else about the druids of Classical times, aside from that they were held in the highest esteem on the Continent. But by the time we have tales of druids appearing in Insular storytelling, their status has fallen - they are little more than seers and wizards. Granted, we are seeing these stories through a Christian lens (more on that later), but we certainly have no affirmative evidence that British druids enjoyed the same status at home as British-trained druids had on the Continent. But point conceded - this is an attested cultural connection between the Gauls and the Britons.
Okay, how about the deities? A handful of names of major cosmological deities mentioned in Continental Celtic inscriptions turn up as "heroes" in the Irish sagas. So it could entirely be the case that these deities reflect an ancestral cosmology. But - as with much actual religious practice in the pre-Christian era - most religious activity appears to have centered not around the cosmological deities, but around local and familial ones, and so the presence of some shared divine names may not mean all that much in the end. The Romanized Gauls found these cosmological deities similar enough to the Romans' to morph them into alternate, localized, forms of the Roman deities, much as the Romans had reconciled the Greek deities and their myths with their own. If anything, this speaks to a potential memory of a common Indo-European cosmology as much as to any particular relationship between Insular and Continental Celts.
In any event, it's entirely possible to have two very distinct culture regions that share a common religion, with one region being the center of religious scholarship for both. One need only think of Arab and Persian Islam as an example, or the fact that English Northumbria, for much of the early middle ages, looked to Gaelic Iona as its center of Christianity, with southern England looking toward Rome. That didn't make the English of Northumbria "Gaelic", much less "Celtic". It just means that cultures have complex interactions with their neighbors, regardless of their linguistic and genetic relationship.
But the discussion of religion reveals another divide between the authentic Celts of the continent in classical times, and the Insular peoples assigned their name in later eras - the Celts were always pagan while they were Celts; they Romanized well before they Christianized. The Insular peoples were Christian from the time they first begin producing records of themselves - and anything we know of their pre-Christian culture comes down to us through the filter of their Christian scribes. The modern imagination of neo-Pagans and Wiccans notwithstanding, the Insular "Celts" were not only Christian, they were the center of Christianity in Northern Europe, the founders and standard bearers of monastic traditions, not to mention Classical learning and knowledge. Of course, there was a time when the Insular "Celts" were pagan, but we know next to nothing about them in this period. To graft an air of paganism onto the modern peoples of Britain and Ireland is counter to everything in their identity. It's the ravings of the Celtomaniac, divorced entirely from history. Even the main source of "ancient Celtic" folk hymns and incantations, beloved and endlessly cited by neo-pagans, the 19th century Carmina Gadelica, is overwhelmingly Catholic in its orientation, besides being not even remotely "ancient".
But moving on, when you think of "Celtic" art, what do you think of? You likely think of knot-work and zoömorphs, like those famously depicted in the Book of Kells. But that style only dates to the early middle ages, and so isn't present in Continental Celtic art at all. Moreover, it's not uniquely Celtic - it's a North Sea style. It's common to the Britons and Irish, true, but it's also shared, with local variations, with the Norse, Danes, and Anglo-Saxons. What about the torc? Well, sure, you see that among Continental Celts AND Britons. And Scandanavians and Anglo-Saxons. And Scythians, Illyrians, and Thracians. Meanwhile, the artistic motifs common among Continental Celts are rare in contemporaneous Britain, and largely appear to be associated with imported goods or their imitations, and not an indigenous style.
When you think of "Celtic" music, what do you think of? Bagpipes! But, of course, Bagpipes were not prominent the Continental Celts or Insular peoples in Classical times, and don't appear to have entered the "Celtic"-speaking portions of the British Isles until the Renaissance reached the islands, after centuries of being the main peasant dance instrument throughout medieval Europe, especially Germany. How about the Harp? Again, unknown among the Continental Celts, or Roman-era Britons, appearing in the early middle ages in Britain (Pictland in particular), spreading outward from there to become popular in differing forms in Europe. So, sure, it was created among "Celtic" peoples, but only if you assume the British peoples were "Celtic".
How about the tune types? Reels, Jigs, Hornpipes? Well, jigs and hornpipes are named after dances, which appear to have first emerged in Anglo-Saxon England; they settled on a tune type much later. The term "reel" appears to derive from Norse. So we have the roots of all the "Celtic" dance tunes in Germanic words. And the oldest dance music we can attribute to who gets called the "Celts" of Great Britain and Ireland, even in their broadest definition, is very recent; recorded in dribs and drabs by others from the 16th century, turning up in occasional manuscripts in the 17th and early 18th centuries, and finally reaching the printing press in the late 18th, or later. And it's in the latter period that the music of people still speaking Celtic languages first begins to appear en masse. This is not to say that the "Celts" of Great Britain had no dance music of their own - it simply shows that by the time we have a historical record of it, the music we think of as indigenous to them is demonstrably part of a long process of cultural exchange with their neighbors, not a naïve tradition produced in perfect, idealized isolation and passed down from the woad-tattooed mists of an imagined past.
But when we look at the "Continental Celts" of Classical fame, and the "Insular Celts" of the early middle ages forward, we see an almost total break, in language, culture, religion. Everything we know of "Celtic Music" can be dated back no further than the 16th century at the oldest, and that's generous, and it's a music that shows evidence of extensive contact with the world around it, not isolation from it.
And here's where the distinction between "Celtic" and "not Celtic", in the case of music, really collapses for me. It assumes that the music of Scotland, Ireland, Wales, Brittany, Cornwall, The Isle of Man, and now Galicia, all developed endogenously from a mythical common ancestor with minimal non-Celtic influence, when - overwhelmingly - these musical cultures are most closely related to those of their nearest neighbors. Breton music is a sister to French folk music. Galician folk music is most closely related to Portuguese and Spanish folk music. And Scottish, Irish, Manx, Welsh, and Cornish folk music are deeply related to, and entangled with, English folk music. Each of these musical cultures absorbed waves of new fashions that emerged from further afield in Europe (or, later, America and elsewhere), and continue to do so - at the same time, sometimes creating an international fad of their own, and sometimes even then coming back - transformed almost beyond recognition - to their place of origin (like the Schottische).
So when we describe "Celtic" music and exclude Playford's English Country Dance music and Morris Dancing and other English forms, we have severed the real link between much of the "Celtic" music of Britain, replacing it with an entirely imagined link to Brittany and Galicia (that's not mediated through shared European flows of culture); moreover, we deny that the "Celtic" peoples of the era when the music we still play was developed to have any agency of their own to import from, adapt locally, or export their music to the majority cultures that were their neighbors, much less any ability to interact with broader European fashion. We lock them into the box of being eternally "primitive", which they weren't.
At the same time, we introduce new absurdities. What about the English-language songs of Ireland? The Scots and Doric songs and instrumental music of lowland and eastern Scotland? This music is somehow still "Celtic", though produced in a Germanic linguistic and cultural context. And these musics borrowed - and shared - as or more heavily with England than they did with their Celtic-speaking neighbors. We've somehow accepted lowland Scotland as "Celtic", in part because they played various form of bagpipe (irrelevant, as we've seen above), and because they shared some tunes with their Gaelic-speaking neighbors, especially since the late 18th century. But for the same reasons, we now hear calls to absorb even-more-English Northumbria into the Celtic fold. But there's no hard boundary, culturally, here - being part of an English linguistic continuum prevents it. The Scots and Northumbrians shared tunes. But so did the Northumbrians and the English midlands, and so on. Much of the music we know of Scotland and Ireland was printed in London, where it went into and out of fashion, and the most important societies for the preservation and propagation of Scottish music were centered there. Shouldn't London then be thought of as a center of "Celtic" music?
Without accepting all of the British Isles as a continuum of musical culture, albeit with strong divergent centers (not coincidentally, in regions where minority languages are strongest), we create an artificial category that seems to exist to exclude the missing link as much as to unite disparate minority cultures.
So where does that leave us? Well, as I said, we're probably stuck with "Celtic" as a marketing term, as inaccurate as it is. "The traditional music of Britain and Ireland" is probably the most accurate, as clunky as that sounds.
Granted, I will not stop doing it - I can't. The term is too deeply ingrained in the imaginations of my potential audiences and clients for me to ditch it. But, more and more, I'm realizing that the term is simply wrong.
To explain why, I have to explain what a "Celt" is.
In modern parlance, the cheeky response is: "A Celt is anyone whose culture is invited to be represented at the Festival Interceltique de Lorient", the huge annual Celtic festival in Brittany. But in more serious terms, the term describes the peoples of the British Isles - excluding the English, but including the Norse-influenced Scots-speakers of Shetlands and Orkney, the lowland Scots themselves, and sometimes the Northumbrians - and their culture; and extended to include the people of Brittany, whether they are Breton- or French-speaking. More recently, this modern definition has been extended to Galicia and Asturias, and it seems to be broadening still. It's only a matter of time before the Basques are admitted as bona fide "Celts".
A more accurate functional definition would appear to be "any ethnic minority indigenous to the Atlantic coast of Europe (excluding most of the North Sea), but including the Irish."
Indeed, the "minority culture" seems to be the main purpose of describing Galicia as "Celtic", to distinguish themselves from other groups in Spain. Certainly there hasn't been an imported Celtic language spoken there since the 9th century AD, when the British colony of Britonnia was reabsorbed into the local population, and no indigenous Celtic language since the last centuries BC, when the region Romanized. When you ask "Why is Galicia 'Celtic'?", you get answers like "We play bagpipes, love to drink and dance, and are superstitious!", which - besides being offensive - would apply equally to almost every rural culture through Europe, regardless of language family, whether Celtic, Germanic, Slavic, or Romance.
With the Scots, Shetlanders, and Orcadians, the reasoning simply seems to be, they live in a country once dominated by Celtic speakers (Gaels), and thus the whole country and all its inhabitants are "Celtic". The same goes for Ulster Scots and the majority of Irish who don't have a functional command of the Irish language. I suppose this also applies to the ethnic English who, because of historic waves of immigration, dominate much of Wales, but not their neighbors in England proper.
By contrast, in historical parlance, a Celt is one of the three broad "nations" of ancient Gaul, along with the Aquitani and Belgae, centered in what is now south-central France. There was an additional group self-identifying in Roman times as "Celtiberians", who claimed to be a blending of Gaulish Celts and the peoples of Iberia. Though the ancient writers did sometimes, especially early on, when contact with them was limited, lump all Gauls under the blanket term "Celt", by the Roman era, they distinguished the Celts from other Gauls - and they always made a strict distinction between Celts or Gauls and the peoples of Britannia and Hibernia. Though some writers described certain tribes of Belgae as living on the south coast of Britannia (and archaeology finds evidence of their towns, or oppidae, there), this only means that the English channel was not a hard border for the Belgae; but at no point does an ancient writer describe a Briton as a "Celt", or had Celts living in Britain (again, because they saw the Belgae as a distinct group of Gauls from the Celts).
So why do we equate the two? Why do we imagine a unified thing called "Celticness" that somehow spans across time and distinct ideological and material cultures?
The story starts with the Scotsman George Buchanan (1508-1582), who, along with the Englishman William Camden (1551-1623), identified linguistic similarities between the contemporary indigenous languages of Britain and elements of the classical place names of the Gaulish peoples living on the European continent, and hypothesized that the Gaels and Gauls might have descended from the same people. This line of reasoning was further developed by the Breton Paul-Yves Pezron (1639-1706) and the Welshman Edward Lluyd (1660-1709), and eventually "educated" people from the British Isles came to draw a direct line of lineage from the Celts of Roman Gaul to the peoples on the fringe of Britain and the northwestern coast of France. A "mania" for all things "Celtic" swept Britain, especially English-speaking elites, tying them to the glories of Rome's greatest foe in the west, and people opined freely about the connections between the continent and the British Isles, desperate to reconstruct the religion, belief, material culture, dress, and the like of the "ancient Celts" to bolster their own identity as English-speaking, but not-English. This mania was, not surprisingly, not shared by actual speakers of what had come to be called "Celtic" languages.
Archaeology bought into this hook, line, and sinker, and quickly the Urnfeld, Hallstatt, and La Tene cultures were immediately identified as Celts, and despite only superficial borrowings of those archaeological culture packages turning up in an insular context, were grafted wholesale in the public imagination onto the islands of Britain and Ireland.
Linguistics did its part. Seeing all the related languages of the Continental Celts and the Britons and Gaels as one fairly close family, it split them not according to grammatical features, but according to whether the Indo-European "k" sound was rendered as a "k", or as a "p". While the Gaels and the Celtiberians used a "k", the Britons and Gauls used "p", and this was used to show that the Celts were once a united "race" (and oh, yes, 19th century notions of race were a big part of this), and that the Britons and Gauls drifted away and innovated relative to the more primitive Gaels and Celtiberians, and spread out from their presumed Alpine homeland in two waves just before entering the historical record.
Nationalism played a role. By claiming that Gaelic had its ancestry in Gaulish, Anglicized Scottish Gael elites, desperate to prove themselves worthy and loyal parts of the British Empire, were able to distance themselves from rebellious Ireland by claiming linguistic descent not from Old Irish, but from the heroic Vercingetorix of Classical lore.
[Oddly enough, the Picts were often excluded from Celtomania. Without the slightest shred of evidence, and despite the fact that Pictish personal and place names are clearly very similar to Old Welsh, the Picts were often assigned "Teutonic", or even "non-Indo-european" status, possibly to assuage the anti-Gaelic nationalism of Scots on the east coast, but certainly because the more a sense of mystery could be contrived around them, the more mystique they accumulated to themselves, and to their then largely Scots-speaking descendants. Indeed, to this day, you'd think "almost nothing is known about the Picts", as if they vanish without a trace at the end of the era of Roman Britain, when in fact they were discussed extensively by Bede and the Annals of Ulster and the Book of Deer, having ongoing relations with both Gael, British, and Northumbrian cultures on their borders.]
But Celtomania was always built on the shakiest of foundations. The cracks should have been visible from the beginning - the same Classical sources mined and extrapolated from in order to create the myth of the Celts also made it clear that the Britons were not Celts, though some tribes of the Belgae appear to have had outposts and towns on the southern coast of Britain. The archaeological cultures associated with the Celts largely never turned up in Britain or Ireland, not for want of searching, except in the form of imported goods.
Linguistics casts significant doubt on the unity of the continental and insular "Celts". The much-vaunted "k/p" shift turns out to be trivial, with numerous examples of it turning up in a range of language families - and this breaks the purported link between Celtiberian and Goidelic on the one hand, and Gaulish and Brythonic on the other. More significantly, the insular Celtic languages, whether they be Goidelic or Brythonic, share major and important innovations absent in the continental languages: the verb-first word order, the mutation of initial consonants, and the pervasive amalgamations of pronouns with prepositions. Some analyses of lexical changes place the break between the insular and continental branches as far back as 3200 BCE +- 1500 years (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC166441/).
Whole-genome DNA studies have been recently casting further doubt. Throughout Europe, the indigenous Neolithic peoples appear to have suffered a major population crash concurrent with the arrival of the Bronze age, with a mere tithe of the genome north of the Mediterranean coast descending from the Neolithic farmers (and fewer still from the Paleolithic hunter-gatherers before them). Most of the region dominated by the "Celts", insular and continental, is dominated by genes from a new population that arose in the Eurasian steppe, likely associated with speakers of Indo-European languages. That much jibes with the myth of the united Celt - but these same studies find little admixture of the Bronze-age populations that settled Britain and the Continent since the time they have occupied these regions - since ~2800 BCE, until the later migrations of historical times (such as the arrival of Anglo-Saxons and then Scandinavians in Britain).
This means that the Continental Celts and Insular "Celts" were very likely as linguistically and genetically isolated from one another as they were with other, non-Celtic, cultures well before the dawn of the Urnfeld culture on the continent, and possibly older than the Bell Beaker culture that preceded it. Furthermore, the break between the Continental and Insular "Celts" could potentially date to early in the expansion from the Eurasian Steppe itself, before arriving in Britain and Western Europe.
The presence of "P-Celts" in Brittany, once part of Gaul, it turns out, is a far more recent affair - these are the descendants of British immigrants in the 5th century, integrated into where large numbers of Britons serving in the Roman Legions had been settled when the legions were withdrawn from Britain itself a century before, and immigration continued in response to the Anglo-Saxon expansion in their homeland in the 6th century. They were not the descendants of Gauls, as earlier writers like Pezron had supposed, but are as much insular "Celts" as their neighbors in Cornwall.
What, then did the Insular "Celts", or rather Britons, and Continental Celts have in common by the time historical sources encounter them? Well, other than languages slightly less distantly related than their common ancestor with other IE language families, not a lot that isn't of a level similar to linguistically less related neighboring groups.
When you think of "Celtic" religion, what do you think of? Okay, Druids. And - I hear some of you reminding me - Caesar assures us that the Druids of Gaul, who were interpreted as a mix of scholars and clerics (akin, perhaps, to the the role of Brahmin in India) were sent to Britain for training. We don't know much else about the druids of Classical times, aside from that they were held in the highest esteem on the Continent. But by the time we have tales of druids appearing in Insular storytelling, their status has fallen - they are little more than seers and wizards. Granted, we are seeing these stories through a Christian lens (more on that later), but we certainly have no affirmative evidence that British druids enjoyed the same status at home as British-trained druids had on the Continent. But point conceded - this is an attested cultural connection between the Gauls and the Britons.
Okay, how about the deities? A handful of names of major cosmological deities mentioned in Continental Celtic inscriptions turn up as "heroes" in the Irish sagas. So it could entirely be the case that these deities reflect an ancestral cosmology. But - as with much actual religious practice in the pre-Christian era - most religious activity appears to have centered not around the cosmological deities, but around local and familial ones, and so the presence of some shared divine names may not mean all that much in the end. The Romanized Gauls found these cosmological deities similar enough to the Romans' to morph them into alternate, localized, forms of the Roman deities, much as the Romans had reconciled the Greek deities and their myths with their own. If anything, this speaks to a potential memory of a common Indo-European cosmology as much as to any particular relationship between Insular and Continental Celts.
In any event, it's entirely possible to have two very distinct culture regions that share a common religion, with one region being the center of religious scholarship for both. One need only think of Arab and Persian Islam as an example, or the fact that English Northumbria, for much of the early middle ages, looked to Gaelic Iona as its center of Christianity, with southern England looking toward Rome. That didn't make the English of Northumbria "Gaelic", much less "Celtic". It just means that cultures have complex interactions with their neighbors, regardless of their linguistic and genetic relationship.
But the discussion of religion reveals another divide between the authentic Celts of the continent in classical times, and the Insular peoples assigned their name in later eras - the Celts were always pagan while they were Celts; they Romanized well before they Christianized. The Insular peoples were Christian from the time they first begin producing records of themselves - and anything we know of their pre-Christian culture comes down to us through the filter of their Christian scribes. The modern imagination of neo-Pagans and Wiccans notwithstanding, the Insular "Celts" were not only Christian, they were the center of Christianity in Northern Europe, the founders and standard bearers of monastic traditions, not to mention Classical learning and knowledge. Of course, there was a time when the Insular "Celts" were pagan, but we know next to nothing about them in this period. To graft an air of paganism onto the modern peoples of Britain and Ireland is counter to everything in their identity. It's the ravings of the Celtomaniac, divorced entirely from history. Even the main source of "ancient Celtic" folk hymns and incantations, beloved and endlessly cited by neo-pagans, the 19th century Carmina Gadelica, is overwhelmingly Catholic in its orientation, besides being not even remotely "ancient".
But moving on, when you think of "Celtic" art, what do you think of? You likely think of knot-work and zoömorphs, like those famously depicted in the Book of Kells. But that style only dates to the early middle ages, and so isn't present in Continental Celtic art at all. Moreover, it's not uniquely Celtic - it's a North Sea style. It's common to the Britons and Irish, true, but it's also shared, with local variations, with the Norse, Danes, and Anglo-Saxons. What about the torc? Well, sure, you see that among Continental Celts AND Britons. And Scandanavians and Anglo-Saxons. And Scythians, Illyrians, and Thracians. Meanwhile, the artistic motifs common among Continental Celts are rare in contemporaneous Britain, and largely appear to be associated with imported goods or their imitations, and not an indigenous style.
When you think of "Celtic" music, what do you think of? Bagpipes! But, of course, Bagpipes were not prominent the Continental Celts or Insular peoples in Classical times, and don't appear to have entered the "Celtic"-speaking portions of the British Isles until the Renaissance reached the islands, after centuries of being the main peasant dance instrument throughout medieval Europe, especially Germany. How about the Harp? Again, unknown among the Continental Celts, or Roman-era Britons, appearing in the early middle ages in Britain (Pictland in particular), spreading outward from there to become popular in differing forms in Europe. So, sure, it was created among "Celtic" peoples, but only if you assume the British peoples were "Celtic".
How about the tune types? Reels, Jigs, Hornpipes? Well, jigs and hornpipes are named after dances, which appear to have first emerged in Anglo-Saxon England; they settled on a tune type much later. The term "reel" appears to derive from Norse. So we have the roots of all the "Celtic" dance tunes in Germanic words. And the oldest dance music we can attribute to who gets called the "Celts" of Great Britain and Ireland, even in their broadest definition, is very recent; recorded in dribs and drabs by others from the 16th century, turning up in occasional manuscripts in the 17th and early 18th centuries, and finally reaching the printing press in the late 18th, or later. And it's in the latter period that the music of people still speaking Celtic languages first begins to appear en masse. This is not to say that the "Celts" of Great Britain had no dance music of their own - it simply shows that by the time we have a historical record of it, the music we think of as indigenous to them is demonstrably part of a long process of cultural exchange with their neighbors, not a naïve tradition produced in perfect, idealized isolation and passed down from the woad-tattooed mists of an imagined past.
But when we look at the "Continental Celts" of Classical fame, and the "Insular Celts" of the early middle ages forward, we see an almost total break, in language, culture, religion. Everything we know of "Celtic Music" can be dated back no further than the 16th century at the oldest, and that's generous, and it's a music that shows evidence of extensive contact with the world around it, not isolation from it.
And here's where the distinction between "Celtic" and "not Celtic", in the case of music, really collapses for me. It assumes that the music of Scotland, Ireland, Wales, Brittany, Cornwall, The Isle of Man, and now Galicia, all developed endogenously from a mythical common ancestor with minimal non-Celtic influence, when - overwhelmingly - these musical cultures are most closely related to those of their nearest neighbors. Breton music is a sister to French folk music. Galician folk music is most closely related to Portuguese and Spanish folk music. And Scottish, Irish, Manx, Welsh, and Cornish folk music are deeply related to, and entangled with, English folk music. Each of these musical cultures absorbed waves of new fashions that emerged from further afield in Europe (or, later, America and elsewhere), and continue to do so - at the same time, sometimes creating an international fad of their own, and sometimes even then coming back - transformed almost beyond recognition - to their place of origin (like the Schottische).
So when we describe "Celtic" music and exclude Playford's English Country Dance music and Morris Dancing and other English forms, we have severed the real link between much of the "Celtic" music of Britain, replacing it with an entirely imagined link to Brittany and Galicia (that's not mediated through shared European flows of culture); moreover, we deny that the "Celtic" peoples of the era when the music we still play was developed to have any agency of their own to import from, adapt locally, or export their music to the majority cultures that were their neighbors, much less any ability to interact with broader European fashion. We lock them into the box of being eternally "primitive", which they weren't.
At the same time, we introduce new absurdities. What about the English-language songs of Ireland? The Scots and Doric songs and instrumental music of lowland and eastern Scotland? This music is somehow still "Celtic", though produced in a Germanic linguistic and cultural context. And these musics borrowed - and shared - as or more heavily with England than they did with their Celtic-speaking neighbors. We've somehow accepted lowland Scotland as "Celtic", in part because they played various form of bagpipe (irrelevant, as we've seen above), and because they shared some tunes with their Gaelic-speaking neighbors, especially since the late 18th century. But for the same reasons, we now hear calls to absorb even-more-English Northumbria into the Celtic fold. But there's no hard boundary, culturally, here - being part of an English linguistic continuum prevents it. The Scots and Northumbrians shared tunes. But so did the Northumbrians and the English midlands, and so on. Much of the music we know of Scotland and Ireland was printed in London, where it went into and out of fashion, and the most important societies for the preservation and propagation of Scottish music were centered there. Shouldn't London then be thought of as a center of "Celtic" music?
Without accepting all of the British Isles as a continuum of musical culture, albeit with strong divergent centers (not coincidentally, in regions where minority languages are strongest), we create an artificial category that seems to exist to exclude the missing link as much as to unite disparate minority cultures.
So where does that leave us? Well, as I said, we're probably stuck with "Celtic" as a marketing term, as inaccurate as it is. "The traditional music of Britain and Ireland" is probably the most accurate, as clunky as that sounds.