In the historic centre of Heraklion, next to Saint Minas Cathedral, the only part of the Old Sinai Monastery of Saint Catherine that is preserved today is its katholikon. Until 1669, when Crete was conquered by the Turks, Saint Catherine had been one of the most important ecclesiastical and spiritual institutes of Orthodoxy. In the 15th century, a school from which famous scholars and hierarchs graduated was in operation within the monastery. The Ottomans converted the monastery into a mosque dedicated to Zulfikar Ali Pasha, and the Sinai monks were transferred to the temple of Agios Matthaios (Saint Matthew). Today, the temple operates as a Museum of Christian Art featuring important works by the Cretan School of Painting – including some of Michail Damaskenos – and other ecclesiastical relics.