The Co-Cathedral of Saint-Antoine-de-Padoue is a co-cathedral in Longueuil, Quebec, Canada, on Montreal's south shore. It is located on the corner of Rue Saint-Charles and Chemin Chambly in the Borough of Le Vieux-Longueuil. It is dedicated to St. Anthony of Padua. The cathedral houses the remains of the Blessed Marie-Rose Durocher, the foundress of the Sisters of the Holy Names of Jesus and Mary.Its episcopal region is Longueuil-Nord. Lionel Gendron, the bishop, has a cathedra sculpted in walnut. Before the reign of Bernard Hubert, it was simply a parish church.The cathedral was classified as historical monument by the Government of Quebec in 1984.HistoryThe site contains the archaeological remains of Fort Longueuil, a fort constructed between 1685 and 1690 as the fortified residence of Charles le Moyne de Longueuil, the only Canadian-born person to be raised to the rank of Baron by the French King. The fort was demolished in 1810 and the cathedral contains stone building materials and elements salvaged from the fort. The site of the fort was designated a National Historic Site of Canada in 1923.