church [Gr. kuriakon = belonging to the Lord], in architecture, a building for Christian worship. The earliest churches date from the late 3d cent.; before then Christians, because of persecutions, worshiped secretly, especially in private houses. In Rome and some other cities Christians worshiped at the martyrs' tombs in the underground cemeteries, or catacombs. The catacomb chapel influenced the furnishing of churches, particularly the crypt. The basilica form came to be standard in Western Europe, while in the East the norm became the square church of Byzantine architecture (see Byzantine art and architecture), derived from the shape of the Greek cross. The interior of the Eastern church is characterized by an image screen (iconostasis) rendering the sanctuary invisible to the lay worshipers, except that the altar may be seen through the doors of the screen. In the West, modifications of the basilica were developed in Romanesque architecture and in Gothic architecture. Renaissance and baroque architecture produced innovations in ecclesiastical design. Western churches in general have an east-west orientation with the altar at the eastern end. In America, Colonial architects developed an austerely beautiful type of spired church, patterned after the works of Christopher Wren and James Gibbs. Churches differ in importance according to their constitution and the position in the hierarchy of their clergy, the cathedral being the bishop's church. See chapel; abbey; Hagia Sophia; Saint Peter's Church; articles on other important churches.