(Greek: krypte, hidden) A secret recess or vault. The origin of the crypts of the Middle Ages was the custom which prevailed in Rome, after the catacombs became disused, of bringing martyrs into the city and burying them in tombs under churches. In the basilicas these tombs were called confessiones. The terms is sometimes applied to the lower story of a two-storied building. Such a crypt might be fully above ground and lighted by windows.