As I mention in Hunting Magic Eels, Celtic Christianity has become very commercialized. There are many authors and speakers who market themselves as purveyors and teachers of "Celtic" spirituality. But lot of that stuff is hokum, warmed over New Age spirituality with an Irish twist.
A case in point is how many modern teachers of "Celtic" spirituality never reckon with the centrality that severe asceticism played within the Celtic monastic tradition. (Paul Kingsnorth is a delightful exception to this rule.) The Celtic saints called this "the green martyrdom," in contrast to the "red martyrdom" of shedding blood for Christ.
For the Celtic Christians there were two ways to die, red or green.
As I describe in Hunting Magic Eels:
The Celtic Christians adored and emulated the Desert Fathers, with their severe fasting, penances, and mortifications...The Celtic monks reveled in nature, but they regularly sought harsh, forbidding locations in which to live. And lacking caves like their heroes the Desert Fathers, the Celtic monks built austere beehive-shaped cells out of stacked rocks. There is a life-affirming sensuality to Celtic spirituality, but Celtic Christian practice was also disciplined and ascetical...And similar to the Desert Fathers, the spiritual potency of the Celtic holy men and women was directly related to the severity of their ascetical practice. The Celtic saints who most severely mortified and disciplined themselves were the ones with the greatest miracle-working powers. For the Celtic Christians, enchantment wasn’t just a frolic among the shamrocks. Magic implied mortification. Enchantment flowed out of ascetical discipline.
...Celtic Christianity loves food, but it also loves to fast. The Celtic Christians called these ascetical practices the “green martyrdom.” (The Celtic word here is glas, which could be translated as “green” or “blue.” Most translators go with “green martyrdom,” but you sometimes see it translated as the “blue martyrdom.”) An old Celtic sermon describes the green martyrdom as “fasting and hard work,” through which Christians “control their desires or struggle in penance and repentance.” Never forget that Ash Wednesday is just as Celtic as Fat Tuesday.
In short, penance, self-mortification, and fasting is very Celtic. Lent is a very Celtic time of year.
Lent is the season of the green martyrdom.

