In ecclesiastical architecture, a ciborium ("ciborion": κιβώριον in Greek) is a canopy or covering supported by columns, freestanding in the sanctuary, that stands over and covers the altar in a basilica or other church. It may also be known by the more general term of baldachin, though ciborium is often considered more correct for examples in churches. Really a baldachin (originally an exotic type of silk from Baghdad) should have a textile covering, or at least, as at Saint Peter's in Rome, imitate one. There are exceptions; Bernini's structure in Saint Peter's, Rome is always called the baldachin. Early ciboria had curtains hanging from rods between the columns, so that the altar could be concealed from the congregation at points in the liturgy. Smaller examples may cover other objects