Only in 1801, this church got promoted to cathedral, when its predecessor, the Saint-Lambert's cathedral was destructed in 1796 during the French Revolution. It is said that its rubble was left till 1826.
There is not much left from the original Romanesque church. Under the sacristy there is still an early Romanesque crypt.
The nave, along with the transept and the choir were rebuilt between 1230 and 1289 in early gothic style. The ceiling in the nave is more recent though.
The parclose and the porch on the north side date from 1334. During the 14th century, the only 100 year old ceiling in the nave was replaced by a high gothic cross ribvaulting construction, giving the opportunity to add high gothic windows in the clerestory. The clerestory was placed on top of the triforium. The vaultal painting date from 1528-1579, and are remarkably well kept.
The western tower was built between the end of the 14th century and 1425. The tower crowning and the spire are from the beginning of the 19e century, along with the triforium under the upper windows. They had to prove the new cathedral status.
The church has interesting stained glass, partially remaining from the 16th century.
The church treasure is remarkable, not at least because of what was recuperated from the ancient cathedral.
On the groundfloor, it has the largest wall gallery from Europe. You will find there a wold-famous bust of Saint-Lambert, made before 1512 in Aix-la-Chapelle, and containing a part of his skull. It is the largest, Late gothic bust.
The gothic pulpit was placed around a pillar.
Another relict of Saint-Lambert is built into a famous, golden sculpture.
In one of the halls at the ground floor, there is an early Christian grave from the 4th century. It comes from around Tongeren.
If you can read French, and want to know more, see Trésor Cathédrale Liège.