Editing Clerestory (section)

===Romanesque period===
During the [[Romanesque architecture|Romanesque]] period, many churches of the basilica form were constructed all over Europe. Many of these churches have wooden roofs with clerestories below them. Some Romanesque churches have [[barrel-vaulted]] ceilings with no clerestory. The development of the [[groin vault]] and [[ribbed vault]] made possible the insertion of clerestory windows.

Initially the nave of a large aisled and clerestoried church was of two levels: [[Arcade (architecture)|arcade]] and clerestory. During the Romanesque period, a third level was inserted between them, a gallery called the "[[triforium]]". The triforium generally opens into space beneath the sloping roof of the aisle. This became a standard feature of later Romanesque and Gothic large abbey and cathedral churches. Sometimes another gallery set into the wall space above the triforium and below the clerestory. This feature is found in some late Romanesque and early Gothic buildings in France.

The oldest glass clerestory windows still in place are from the late eleventh century, found in [[Augsburg Cathedral]] in [[Bavaria]], Germany.