As in most churches, the cathedral’s plan forms a Latin cross. The transept forms the horizontal arm of the cross. The space at the intersection of the cross is called the transept crossing.
This volume is proportional to the dimensions of the cathedral. Liturgical celebrations take place in this space. The two arms of the transept are also called transept arms.
The north rose window has preserved its almost intact original 13th-century stained glass, while the south rose window, offered by Saint Louis, was largely restored in the 18th and 19th centuries.

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