Ecumenical Patriarch Bartholomew the First led the world's Orthodox Christians in celebrating Easter yesterday.

Western and Eastern churches celebrate Easter on different dates because they use different calendars. Protestant and Roman Catholic churches follow the Gregorian Calendar, while Orthodox churches use the older Julian Calendar.

Bartholomew blessed more than one-thousand worshipers at the Cathedral of St. George in Istanbul, Turkey, which is built atop ancient Constantinople.

In Moscow, Russian Orthodox leader Patriarch Alexy the Second led a five-hour Easter service.

With President Russian Vladimir Putin and his wife in attendance, Alexy urged Israel to end its siege of Bethlehem's Church of the Nativity, which was occupied by armed Palestinians a month ago.