Pentecost is 50 days after Easter (Pascha). Pentecost literally means 50th day. It is one of the 7 seasons of the Church. Pentecost was originally an Old Testament festival, since the time of Josephus calculated as beginning on the fiftieth day after the beginning of Passover. In the Christian calendar, it falls on the seventh Sunday after Easter. It was called the Feast of Weeks (Shavuot), and in the Old Testament was originally an agricultural festival celebrating and giving thanks for the first fruits of the early spring harvest (Lev 23, Exod 23, 34).... In most Christian traditions, Pentecost Sunday occurs 50 days following Easter Sunday (counting Easter Sunday since it is the first day of the week). Those 50 days span seven Sundays after Easter, so Pentecost is the seventh Sunday after Easter (7 weeks times 7 days = 49 days, plus Pentecost Sunday). Since Easter is a ?movable feast,? meaning that it occurs on different days in different years (it is tied to the lunar cycle while the calendar is solar based), Pentecost is also moveable. It can occur as early as May 10 and as late as June 13 (see The Church Year for current dates). Some Christian traditions, Eastern Orthodox for example, use a different religious calendar and so have different dates for much of the Christian Year. http://www.crivoice.org/cypentecost.html