Per a suggestion from my friend Jules, I’m going to do a series of reading lists on different mythologies — Celtic, Norse, Greco-Roman, and so on. Here’s the first entry, on Celtic myth. It’s hard to talk coherently about this subject because unlike the Greeks, who heplfully lived in Greece, the Celts covered most of Europe at one time or another and are chiefly identified by the fact that they spoke related languages. But a pagan in first-century southern Britain did not necessarily believe the same things as one in Ireland, or another in Pictland. And whereas the Greeks and Romans were kind enough to write down all of their myths in blooks clearly labeled “all of our myths,” the Celts didn’t do that. According to Julius Caesar, in fact, the druids were prohibited by the tenets of their religion from writing any of it down, which is upsetting. To reconstruct anything like “Celtic” (or just Welsh, or just Irish, or…) myth, we’ve got to pick through a heap of disparate sources, written long after paganism had ceased to be a going concern. Fortunately, that includes some of the best stuff ever written in Europe, so let’s go.
Primary Sources (Welsh)
The Mabinogion, trans. Sioned Davis
This is a collection of Welsh prose tales including the Four Branches of the Mabinogion, which are related in some arcane way that no one fully understands (it’s not actually clear why they’re called that), the oldest Arthurian romance (“romance” in the medieval sense of “adventure story in the vernacular,” not “love story,” although it kind of is that too if you squint), Welsh versions of the famous tales of Chretien de Troyes, and more. It’s so good man you gotta read it. Davis’ edition is fantastic, with brilliant and copious endnotes. It does, unfortunately, omit the Hanes Taliesin, which is much later than the other texts. I also published on this once but y’know no pressure.
The Book of Taliesin, trans. Gwyneth Lewis and Rowan Williams
A collection of Welsh poetry in translation. Much of it is riddling and allusive and mysterious and it rules, especially Cad Goddeu, in which a wizard brings an army of trees to life to fight a monster. The chant in Duel of the Fates, by the way, is that poem translated into for some reason Sanskrit. Many of the texts here will make more sense if you read the Mabinogion first.
Trioedd Ynys Prydein: The Triads of the Island of Britain, trans. Rachel Bromwich
This is a deep cut, and not easy reading. The triads are little fragments of myth, history, literature and folklore that probably served as a mnemonic device. Many of the stories or references they preserve are lost to us now, and they all sound like this:
Three atrocious axe-strokes of the island of Prydain:
The axe-stroke of Eidyn on the Head of Aneiryn;
and the axe-stroke on the head of Godlan the bard;
and the axe-stroke on the head of Iago son of Beli.
and no one knows what half of that means. You can read many them for free here, but without a pretty robust knowledge of Welsh tradition and British history from about 4-700 you might not get much out of them. Bromwich was one of the best to ever do it, and her analyses and notes are fantastic, so if you’re looking to max out your Welsh background I’d grab her book. Alternatively, you may want to look through the Thirteen Treasures of the Isle of Britain — clicking through all of the wiki links here will give you a pretty decent background.
Primary Sources (Irish)
The mythological history of Ireland begins with the Lebor Gabála Érenn, or the Book of Invasions, which is hard to find in print. I’d suggest reading the wiki summary, and then these two texts (free online):
The First Battle of Mag Tuired
A battle between the Fir Bolg and the Tuatha Dé Danann (the people of the goddess Danu), the race of Irish gods.
The Second Battle of Mag Tuired
The Tuatha fight off the Formorians, a weird race of underworld dwellers. Lots of the most famous bits of Celtic myth — magic cauldrons, the eye of Balor, how Nuada lost his arm — appear here.
With a good background in the mythological cycle of Ireland, you can now move on to the later heroic cycles:
The Táin Bó Cúailnge, trans by. Carson or Kinsella
An Irish epic. Queen Medb (you are really going to want to google how some of these names are pronounced), who is probably a goddess, touches off a war between Connacht and Ulster involving the legendary hero Cú Chulainn, son of the god Lugh. It gets compared to the Iliad a lot and, like, kind of?
Early Irish Myths and Sagas, trans. by Jeffrey Gantz
This is what it says on the tin. A collection of myths and sagas, many involving Cú Chulainn, with occasional druids.
And for general folklore and religion, including the sacred ever-burning fire tended only by women which is almost certainly a pagan holdover and also werewolves, check out Gerald of Wales’ History and Topography of Ireland. He’s got one on Wales, too.
Primary Sources (General/Other)
The Celtic Heroic Age, John T. Koch
I think this is out of print, which is a shame, because it’s a great collection of hard-to-find sources in translation. The first section is ancient Greek and Roman writing about the Celts, the second is on Irish material, and the third is on Welsh. There’s an older edition which goes for much cheaper on Amazon, but I don’t have that version and I don’t know what the differences are. That first edition is also available for free on archive.org.
Can’t leave out the Breton material. This a collection of Breton lays — narrative poems — filled with faeries and otherworld journeys. Also werewolves, again.
From the Academy
The Gods of the Celts, Miranda Aldhouse-Green
A few decades out, some of the scholarship in this work has been superseded, but it remains an excellent introduction to Celtic myth and religion. You might also like her more recent Sacred Britannia, which focuses on the period during which Britain was a part of the Roman empire.
A survey of the pagan religions of Britain. Like, all of them — prehistoric, Celtic, Anglo-Saxon, Norse… Hutton is one of the best writers on this subject, and this is maybe his best book.
Celtic Heritage: Ancient Tradition in Ireland and Wales, Rees and Rees
This is an overview of the Welsh and Irish mythological material from a comparative religion standpoint. Brilliant, but may be a bit dry if you’re not in the mood for academic prose.
Elf-Queens and Holy Friars: Fairy Beliefs and the Medieval Church, Richard Firth Green
A little off topic, this book is not really about Celtic mythology but the faerie cult in medieval Europe, which has roots in Celtic myth and Germanic myth and probably a bunch of other places. Comprehensive and a pleasure to read.
Bonus Points: The Lives of the Celtic Saints, featuring King Arthur (sometimes)!