The Revised Common Lectionary (RCL) is an ecumenical three year cycle of Bible readings used by many churches throughout the world. It follows the seasons of the Christian year and begins each year with the first Sunday in Advent (which usually falls on the last Sunday in November).
The lectionary offers congregations a balanced diet of readings for each Sunday of the year, drawn from the Hebrew Scriptures, the Psalms, the Epistles and the Gospels.
Lectionaries were known and used in the fourth century, where major churches arranged the Scripture readings according to a schedule which follows the calendar of the church's year. This practice of assigning particular readings to each Sunday and festival has continued through the history of the Christian Church.