Hildesheim Cathedral, officially the Cathedral of the Assumption of Mary or simply St. Mary's Cathedral, is a medieval Roman Catholic cathedral in the city centre of Hildesheim, Germany, that serves as the seat of the Diocese of Hildesheim. The cathedral has been on the UNESCO World Cultural Heritage list since 1985, together with the nearby St. Michael's Church.
The cathedral church was built between 1010 and 1020 in the Romanesque style. It follows a symmetrical plan with two apses, that is characteristic of Ottonian Romanesque architecture in Old Saxony. The cathedral's treasures include world-famous artworks, bronze works from the time of Bishop Bernward, Bernward Doors and Bernward Column, as well as two of the four notable Romanesque wheel chandeliers: the Hezilo chandelier and the Azelin chandelier.
After renovations and extensions in the 11th, 12th and 14th centuries, the cathedral was completely destroyed during an air raid on 22 March 1945 and rebuilt from 1950 to 1960. A thorough renovation of the cathedral began in 2010, including technical and conservation measures.