Easter/ Paschal/ Eostre/etc. etc. etc. is proving a tough nut to crack. The problem is that it's not tied to any specific date; it can occur anytime between March 22 and April 25. When one adds Lent into the calculation, the start potentially goes back as far as February 10. Add Carnival/ Cwarmê/ Fastelavn/ Shrovetide/ Fasching/ Fastnacht/ Vastenavond/ etc., which happens before Lent, and the period is extended even longer. Usually another week. And then the transition from the Julian to the Gregorian calendar complicates things yet more.
As such, the whole thing tends to "sweep up" pre-Christian practices and beliefs during that three month time period like a deep sea fishing net. Parsing them all out is a bitch and a half. But still the work continues!