Several buildings were erected and destroyed on this site, until in 990 Bishop Haimont ordered the construction of a new cathedral on the Romano-Rhenish plan: a nave, two transepts, two opposing apses, each one flanked by two belltowers.
In the 12th century, the architect Garin built the east choir, the two portals of Saint John and of the Lion, and the crypts.
[2] In the 14th century, the cathedral was refurbished in the Renaissance style; the flat wooden ceiling was replaced by a vaulted one, the windows were enlarged, and the interior was decorated with frescos.
The cathedral was badly damaged, and from 1760 was overhauled in the Neo-Classical style, of which the principal works are the refurbished nave, the east tower, the organs, and especially the magnificent Rococo baldacchino.
[4] The cathedral was severely damaged during World War I between 1916 and 1917; the eastern block was totally destroyed, and the towers have never been rebuilt.