The vault of Beauvais Cathedral first collapsed in 1284.
The disaster occurred about twelve years after the cathedral's choir was completed in 1272. Some of the recently finished vaulting gave way, interrupting construction and forcing medieval builders to reconsider how such an exceptionally tall structure could be stabilized.
During the rebuilding, additional supports were introduced and the vaulting system was changed from quadripartite to sexpartite vaults. The choir was reconstructed at nearly the same ambitious height, preserving Beauvais's claim to the tallest Gothic interior while making the structure more robust.
The 1284 collapse was not the cathedral's only structural catastrophe. In 1573, a massive tower at the crossing collapsed, damaging parts of the transept and choir. Work then effectively stopped, leaving Beauvais unfinished. Its history illustrates both the daring of Gothic engineering and the risks of concentrating enormous loads and lateral forces in thin masonry walls and buttresses.