The Cathedral of Saint Bavo is a religious building in Haarlem, the Netherlands, built by the Catholics from 1895 to 1930 to replace the former waterstaatskerk in the Jansstraat called the St. Joseph. That church was itself a replacement for the Sint-Bavokerk, that had been converted to Protestantism from Catholicism in 1578. The Cathedral of Saint Bavo now serves as the main cathedral for the Roman Catholic Diocese of Haarlem-Amsterdam. Within the Cathedral, the former sacristy has been converted into a small museum (schatkamer) containing historical artefacts from Haarlem's Catholic past.