The Transept's Development From Early Basilica To Gothic Cathedral

Transepts appear in Christian building as early as the fourth century, with Old Saint Peter's Basilica in Rome commonly cited among the earliest examples of a transverse hall inserted between the nave and the apse of an otherwise standard basilical plan, though early transepts of this period did not always rise to the full height of the nave or read as strongly as a cross shape from the exterior. The transept became a genuinely standard, structurally emphasized element of Western church architecture through the Romanesque period, when builders increasingly gave the crossing its own raised tower and treated the transept arms as full architectural statements in their own right rather than modest side extensions, a development that carried forward and intensified into the Gothic cathedrals of the twelfth and thirteenth centuries, where transept facades were sometimes given their own elaborate portals and, in French Gothic examples especially, their own large rose windows to match the west facade.

Eastern Christian church architecture developed the cross-shaped plan along a somewhat different path, favoring centrally planned domed churches, such as the cross-in-square plan standard in Byzantine architecture from the middle Byzantine period onward, in which the arms of the cross are typically shorter and more evenly balanced around a central dome than in the elongated Latin-cross plan characteristic of Western cathedrals.