A Brief Deconstruction of “Celtic Spirituality”

One of the things that comes up for me a lot when I am designing my programs about the spiritual traditions of the British Isles is what to call this field of study.
Do I say Celtic? Insular Celtic? Iron-Age? Ancient British? Is it accurate to say “spiritual traditions”, when most likely spiritual beliefs infused every part of life of the ancients? Is it better to say “cosmology”, when cosmology refers to a wide range of cultural practices and worldviews, not just spiritual beliefs, even though my focus is on the spiritual side of things, and even though you can’t actually separate these?
Let’s start with Celtic. This word is thrown around a lot, and it can have specific meaning in some instances, and be so vague as to be meaningless in others.
The word “Celtic” actually only has a specific definition in the field of linguistics. Today, there are 5 surviving Celtic languages, and one that has only recently become extinct (Cornish, and blessings to those championing the revival!). Language, of course, is vitally important to culture, but it doesn’t encompass everything.
So, what does it mean to speak of “Celtic cultures”? Can we really even do this? Well, in my view, this is a lot murkier. While this is somewhat vague as a term (it would be a lot more accurate to say, “Scottish”, “Gaulish”, “Welsh” etc.), it still points to something, and there are entire nations embedded in a Celtic identity.
Often when we hear the word today, we think of Ireland or Scotland, or we think of a static snapshot of some time in the distant past where people danced with fairies in the greenwoods of Britain, and played the harp.
But actually Celtic cultures have, at one time or another, existed over a wide expanse of Europe, and over several millennia. There are of course great complexities within this as well, with various different eras marked by cultural variation within this time and geographic frame. Generally speaking, the Celtic era is understood to have started in the late Bronze Age, having a stronghold throughout the Iron Age (approx. 800 BC - 100 AD in the British Isles).
The Celtic identity and languages are also still very much alive today, particularly in the British Isles (Irish, Welsh, Scottish, Manx, and Cornish), and so it’s incorrect to see Celticity as something only from the past, or something that has ended.
However, when we hear people speak of “Celtic spirituality”, usually what they are referring to are the practices and worldview of the Celtic nations of Britain before the Roman invasion, which is roughly between 700 BC - 50 AD. However, it of course carried on during the Roman occupation that ended around 400 AD, and has survived and adapted ever since throughout many invasions and changes until today.
The trouble with saying “Celtic spirituality” without making room for these nuances is that there is an awful lot of ambiguity in our practice and study - and unfortunately, misinformation about what falls under this umbrella.
One way that I found to be more clear is to say, “Insular Celtic”. This term refers specifically to the Celtic languages of the British Isles, and I tend to use it to indicate that my work focuses on this geographical area. However, I know there are still a lot of limitations with this term - for example, it still only strictly refers to language, and I am not teaching any of the Celtic languages, but the worldview in a spiritual context. It also indicates that these cultures are homogenous with the same lore and traditions, when this is absolutely not the case.