i was hoping to find some documentation of the obvious solstice festival that st. patrick's replaced. i'm not going to do the math or look up how close march 17th would have been to the solstice, through whatever gregorian/julian conversions, in the third or fourth century of the common era. it hardly seems worth the effort; the deduction is obvious.
the closest thing i could find was an association with a kind of fertility cult that comes off as something out of a gimbutas text. that kind of makes sense, at least, but if it's true then we've lost the narrative - all we have is some sculptures.
so, it appears that we don't even know what festival st. patrick's day replaced. that's how brutally colonized we are.