The reconsolidation of the bell tower of the cathedral of Cologne, undertaken in 1980, is the occasion for retracing the history of its construction in the 15th century. Its bells, which are reputed for their perfect sonority, were founded in the 15th century and in the 19th century. The restoration included the bells, armature, and metal mounting. The restorers were particularly dedicated to preserving the quality of the sound. -- AATA