I think I figured why we get our Easter candy 50% off...

I've always wondered what the difference between Greek Easter and American Easter was, and the explanation I've always gotten in my family is that it's because of a disagreement of when some specific events happened, but it's actually a difference of opinion between which calendar type of calendar should be used.

Greek Easter is still calculated on the Julian calendar (created under Julius Caesar in 46 B.C.) , which is about 13 days behind the more modern Gregorian calendar (which was adapted after the Julian calendar because the mean year in the Julian Calendar was slightly too long, causing the vernal equinox to slowly drift backwards in the calendar year). Greek Orthodox Easter should fall on the Sunday that follows the first full moon after the spring or vernal equinox. So basically, it's not a disagreement between Eastern Orthodox churches and other sects, but a dedication to a less accurate calendar system that causes Greek Easter to always be later in the year.

However, looking a little further I found out that the calendar is not the only difference between Greek Orthodox and other sects of Christianity. The Great Schism between the Roman Catholic and Eastern Orthodox relgions occured because of two fundamental disagreements:

1. The Filioque Clause:

In Christian theology the filioque clause or filioque controversy (filioque meaning "and [from] the son" in Latin) is a heavily disputed part of the Nicene Creed, that forms a divisive difference in particular between the Roman Catholic and Eastern Orthodox traditions. In the Orthodox tradition, the line in question reads "We believe in the Holy Spirit ... who proceeds from the Father", while in the Catholic tradition it reads "We believe in the Holy Spirit ... who proceeds from the Father and the Son". It is most often referred to as simply "filioque" or "the filioque."

Basically, Eastern Orthodox faith thinks interpreting it "We believe in the Holy Spirit...who proceeds from the Father and the Son" is inaccurate. They argue that the Bible does not "say explicitly that the Holy Spirit proceeds from the Son as well as the Father". This, in part, is what caused the Great Schism in 1084.

2. The authority of the Pope:

Eastern Orthodox theology makes that case that:

There is no single leader in the church. No pope. All bishops are equal. The Patriarch of Constantinople has the distinction of acting as “president” of any ecumenical council, should one be called (the last one was in 787AD), for this he is called “First Among Equals".

http://orthodoxwiki.org/Main_Page
http://www.religionfacts.com/christianity/denominations/orthodoxy.htm
http://www.smart.net/~mmontes/ortheast.html
http://www.slocc.com/orthodoxy/

Other than that, it's the same.