 It contains an organ by the organ-builder Joseph Valtrin, installed in 1752 and now classed as an historic monument in its own right.On 3 November 1979 the Diocese of Belfort–Montbéliard was created from part of the territory of the Archdiocese of Besançon.The seat of the bishop was established at Belfort, and St. Christopher's Church was elevated to the status of cathedral.