The cathedral of Lièges has been a monastery church until 1797. It only became a cathedral after the demolition of St Lambert (which was located in front of the palace of the Prince-Bishops) through friends of the French Revolution. A worthy replacement.
The cathedral you can visit today is following the aesthetic ideas of the 19th century, though there is still a lot of ‘original’ art from past centuries. Despite its eclectic nature, the overall impression of this church is breathtaking, though. We are looking at a building from the 13th centuries (with a Romanesque predecessor) which was often modified until today. The 19th century refurbishment of Lièges cathedral signified the purity of lines in this building: pillars with cylindric pedestals, acanthus decorations of the capitals, a well-defined triforium, and the lancet windows in the apses.