The custom of turning toward the East in prayer, already in practice in pre-Christian times. Christianity attached a new significance to the ritual. The East was the cradle of human civilization. Christ lived in the East while he was on earth, and from the East he will come to judge the human race. The Apostolic Constitutions (from 900 on) directed that churches be erected with the apse toward the east. This custom was observed except by Emperor Constantine, so that the churches of St. John Lateran, St. Peter, and San Lorenzo, violate that directive. Later the directions of city streets made this custom impracticable. The altar end, regardless of its situation, is always referred to as the east end, and caskets at funeral Masses are placed with a priest's head to the east and a layman's feet to the east, symbolizing the relative position of priest and people at divine services.