Which "Pagan" festival in 5th C Britain fell on the first Sunday after the full Moon that occurs on or after the spring equinox?
What you are saying is that druids millennia previously perhaps held a festival on a different date but roughly similar date, therefore every other spring festival held for any reason is just a copy of that, even if the people who "copied" it had no knowledge of it and celebrated on a different date for completely different reasons and even imported the date from foreign lands where British druidry was completely irrelevant.
Might as well say the spring bank holiday is "Pagan", or half-term is "Pagan". Actually, might as well just say celebrating things is "Pagan"...
It wasn't only eater either,this is from "The golden Bough" by Sir James George Frazer:
What considerations led the ecclesiastical authorities to institute the festival of Christmas? The motives for the innovation are stated with great frankness by a Syrian writer, himself a Christian. “The reason,” he tells us, “why the fathers transferred the celebration of the sixth of January to the twenty-fifth of December was this. It was a custom of the heathen to celebrate on the same twenty-fifth of December the birthday of the Sun, at which they kindled lights in token of festivity. In these solemnities and festivities the Christians also took part. Accordingly when the doctors of the Church perceived that the Christians had a leaning to this festival, they took counsel and resolved that the true Nativity should be solemnised on that day and the festival of the Epiphany on the sixth of January. Accordingly, along with this custom, the practice has prevailed of kindling fires till the sixth.” The heathen origin of Christmas is plainly hinted at, if not tacitly admitted, by Augustine when he exhorts his Christian brethren not to celebrate that solemn day like the heathen on account of the sun, but on account of him who made the sun. In like manner Leo the Great rebuked the pestilent belief that Christmas was solemnised because of the birth of the new sun, as it was called, and not because of the nativity of Christ.
Thus it appears that the Christian Church chose to celebrate the birthday of its Founder on the twenty-fifth of December in order to transfer the devotion of the heathen from the Sun to him who was called the Sun of Righteousness. If that was so, there can be no intrinsic improbability in the conjecture that motives of the same sort may have led the ecclesiastical authorities to assimilate the Easter festival of the death and resurrection of their Lord
Makes sense?,i think so.
Philippe Walter, professor of medieval French literature at the University of Grenoble III, says in his book
Christian Mythology that "in the process of the Christianisation of pagan religions", it was easy to associate the pagan festival that celebrated "the passage from the death of winter to the life of springtime" with Jesus's resurrection.
It was a key step in introducing "Christian commemorations" to the pagan calendar, he says, smoothing the way to mass conversion.
It's not difficult to see whats going on here,it's a strategy of the church to convert and makes absolute sense.