The modern drama does not originate in the ancient, but in the religious plays of the Middle Ages, themselves an outcome of the liturgy of the Church. Ecclesiastical worship was thoroughly dramatic, particularly the Holy Mass, with its progressive action, its dialogue between the priests and their ministers at the altar, or, on feast days, between the officiating priest and his assistants, with the choir of singers, and the people. Often — e.g. at Christmas, Epiphany, and Easter — the text of the Gospel called for a variety of roles. The celebration of the feasts was as rich and varied as they were numerous; poetry and music, in particular, helped to impress properly on the laity the full significance of the great events commemorated.