The vast majority of the Christian world celebrates Easter next weekend, but not all of Europe celebrates it on the same date. While for Roman Catholics and Protestants, Easter Sunday is on 5 April, for the Orthodox of various denominations, the celebration takes place a week later.
Why is this? To understand, you have to go back more than four centuries and ask what European Catholics did between 5 and 14 October 1582. The answer will surprise you: they didn't actually do anything. That's because those days didn't exist, but automatically moved from the 4th to the 15th.
