Treasure: I don't think the different Easter dates have anything to do with that, but rather with the fact that we still calculate easter time according to the julian calendar despite switching to the gregorian one in 1923...
ZFR: Julian/Gregorian calendar is only one part of the reason (that accounts for the "big" difference (0 or 1) vs (4 or 5)). The other part (the reason why there is a "small" 1 week difference) is due to the different methods in calculating the lunar phase.
This year we get both combined, so there is a massive 5 week difference between the two.
The Western Easter is more "astronomically" accurate, but the Eastern Easter always takes place
after Passover, so it's more "religiously" accurate.
I have parents from both backgrounds so we celebrate both Easters. Unless of course they fall together anyway.
EDIT:
As a side notice, some Christians up till recently (not sure if still) had yet another method of calculating Easter. Basically, while most Christians celebrate it on Sunday, the same day of the week Jesus was resurrected, they'd instead celebrate it on the same day of the
month Jesus was resurrected, as per to the Hebrew calendar, which is a day or 2 after Passover, not necessarily on a Sunday. Not sure who exactly does/did this, but I vaguely recall it being practiced by a few communities somewhere in Georgia/Caucasia. I could be mistaken though.
Thanks for the correction. :-) I had completely forgotten the "doing the easter after jewish passover" thingy, but then I'm not really of the kind that pays attention to jewish traditions (I actually prefer the new testament over the old). And yes, I guess it's better when both easters fall together because there isn't this kind of weirdness as happened this year... Also, the fact you're going to celebrate orthodox easter as well sounds good. (as well as the extra info of yet another way of calculating easter) :-)
