The Orthodox Church year is governed by a Calendar which marks the events and commemorates persons that are of particular importance to Orthodox Christians. The Church year begins on September 1, the day on which the civil calendar of the Later Roman Empire began. Every day in the Christian year is sacred to the memory of some Saint or memorable event in the history of the Church. Some Saints and events are always remembered on the same day each year; these commemorations are called Fixed Feasts. Other Feasts whose dates depend on the date of Easter are called Movable Feasts.