Toward the end of the 9th century, Moorish pirate havens were established along the coast of southern France and northern Italy. In 846 Moor raiders sacked the "extra muros" Basilicas of Saint Peter and Saint Paul in Rome. In 911, the bishop of Narbonne was unable to return to France from Rome because the Moors from Fraxinet controlled all the passes in the Alps. Moor pirates operated out of the Balearic Islands in the 10th century. From 824 to 961 Arab pirates in the Emirate of Crete raided the entire Mediterranean. In the 14th century, raids by Moor pirates forced the Venetian Duke of Crete to ask Venice to keep its fleet on constant guard.