In the later Middle Ages the Muslim states of North Africa had by and large been fairly pacific. Although there had always been a certain number of corsairs amongst their populations, they were certainly not renowned for their bellicosity and for their prosecution of jihād against the Christian infidel at sea. Indeed, in the fourteenth and fifteenth centuries it had been Christian, and particularly Catalan, corsairs who had been the major threat to maritime traffic in the western Mediterranean. According to Ibn Khaldūn, Maghrebin pirates and corsairs first assumed serious dimensions around 1360 at Bougie. By 1390 corsairs operating from Tunisia had become a severe enough menace to Christian shipping to provoke Genoa to organize a Crusade against Mahdia. Native Maghrebins and Moorish exiles from Spain were always to remain active as corsairs in North Africa throughout the fifteenth and sixteenth centuries, but it was Ottoman corsairs under Kemāl Reis, moving to the Maghreb around 1487, who ushered in the great days of the Barbary corsairs. The move to the Maghreb was a logical extension of the Ottoman push westwards to the shores of the Ionian; however, as we shall see, it was not to offer the Barbary corsairs the same logistical advantages that the push to the west coasts of the Balkans did the Ottomans.