The Speyer Cathedral, officially the Imperial Cathedral Basilica of the Assumption and St Stephen, in Speyer, Germany, is the seat of the Roman Catholic Bishop of Speyer and is suffragan to the Archdiocese of Bamberg. The cathedral, which is dedicated to St. Mary, patron saint of Speyer and St. Stephen is generally known as Imperial Cathedral of Speyer. Pope Pius XI raised Speyer Cathedral to the rank of a minor basilica of the Roman Catholic Church in 1925.
Begun in 1030 under Conrad II, with the east end and high vault of 1090-1103, the imposing triple-aisled vaulted basilica of red sandstone is the "culmination of a design which was extremely influential in the subsequent development of Romanesque architecture during the 11th and 12th centuries". As the burial site for Salian, Staufer and Habsburg emperors and kings the cathedral is regarded as a symbol of imperial power. With the Abbey of Cluny in ruins, it remains the largest Romanesque church. It is considered to be "a turning point in European architecture", one of the most important architectural monuments of its time and one of the finest Romanesque monuments.
In 1981, the cathedral was added to the UNESCO World Heritage List of culturally important sites as "a major monument of Romanesque art in the German Empire".