The former Roman Catholic Diocese of Ypres, in present-day Belgium, existed from 1559 to 1801.[1] Its seat was Saint Martin's Cathedral in Ypres. In 1969 it was reconstituted as a titular see.
The diocese was originally part of the Diocese of Thérouanne, which had been established in the 7th or 8th century. In 1553 Charles V, Holy Roman Emperor besieged the city of Thérouanne, then a French enclave in the Holy Roman Empire, in revenge for a defeat by the French at Metz. After he captured Thérouanne, he razed the city. In 1557, as a result of the war damage to its see, the diocese was abolished. This led to a reform of sees at the Council of Trent and the bishopric of Thérouanne was split between the Diocese of Saint-Omer, the Diocese of Boulogne and the Diocese of Ypres. With this, Saint Martin's Church was elevated to cathedral status, as it became the see of the new diocese.
After the Concordat of 1801 between Napoleon and Pope Pius VII, Ypres was incorporated into the Diocese of Ghent, and Saint Martin's lost its status as a cathedral.
Cornelius Jansen, the father of the theological movement Jansenism, was Bishop of Ypres from 1635 to 1638.
