crypt [Gr.,=hidden], vault or chamber beneath the main level of a church, used as a meeting place or burial place. It undoubtedly developed from the catacombs used by early Christians as places of worship. Early churches were commonly built over the tombs of martyrs. Such vaults, located beneath the main altar, developed into the extensive crypts of the Middle Ages that in many churches of the 11th and 12th cent. occupied the entire space beneath the sanctuary. At Canterbury the 12th-century crypt forms a large and complete lower church in itself. The crypt of the Rochester Cathedral is partly above ground. The cathedrals at Chartres and at Bourges have crypts typical of the Gothic development.

Subterranean chamber, usually under a church floor. The catacombs of the early Christians were known as cryptae, and when churches came to be built over the tombs of saints and martyrs, subterranean chapels were built around the actual tomb. As early as the reign of Constantine I (AD 306–37), the crypt was considered a normal part of a church. Later its size was increased to include the entire space beneath the choir or chancel; the crypt of Canterbury Cathedral is an elaborate underground church with its own apse. Many secular medieval European buildings also had richly decorated crypts.

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