I’m once again feeling wearied by all the nonsense (pagan and fundamentalist Christian in equal doses) about how the date of Easter was the result of some sort of deliberate paganizing conspiracy. Personally, I don’t like the modern trappings of Easter. A lot of the secular symbolism (rabbits, eggs) does derive from (isolated, not universal) pagan symbols, adapted (clumsily) as they were to “Christianize” populations. That sort of thing was a blunder that has now ruined a holy day.
But setting that aside, arguing a pagan conspiracy for the date is nonsense. Sorry folks, but ANY calendar / time-keeping in the ancient world had to be done using either lunar or solar cycles. Those are the celestial bodies Genesis talks about times and seasons. Paganism didn’t appropriate the objects in our solar system.
The reasons for the date calculation are partly cultural, astronomical, and mathematical. The issue was also tied to the Gentile-Jewish tension within the church of antiquity. Why? Because Gentiles and Jews had different calendrical methods (solar vs. lunar). Christianity was not restricted to Judah or to the Jews (surprise), and so the Mediterranean Roman empire in which Christianity found itself didn’t bother to ask the Jewish Sanhedrin if it could keep its calendar. In other words, there were a whole lot more Gentiles than Jews in the early church — it’s about demographics and sheer numbers. No conspiracy needed.
If you’re interested in this issue, here’s an excellent article about it. Here’s an excellent, detailed scholarly book on it. If you have access to journal databases, I especially recommend Henry Chadwick’s article: “The calendar: Sanctification of time,” Irish Theological Quarterly 66, no. 2 (2001): 99-107.