Kenneth Setton  

"Long before pope Urban II made his impassioned plea at Clermont, the Italian cities were fighting the Saracens on land and sea. During the four centuries preceding 1095 they suffered from seemingly endless raids and plunderings; sometimes they allied themselves with the enemy to attack other cities; on occasion they they met him with force, and these occasions increased in number and gained in success. ... Finally, in the eleventh century the Pisans and Genoese raided the African coast itself, and forced terms of peace upon the Saracen leader, among them the promise to refrain from further piracy. With this victory and peace, made in 1087, control over the western Mediterranean passed from the Arabs to the Italian cities.

The first period of Italo-Arab relations ran from 652 to 827. During these years the Arabs attacked and plundered the south Italian cities almost at will, because the Byzantines and Italians were unable to maintain garrisons everywhere. The attackers shifted their raids in accordance with the Italian defense and preparedness. But they remained mere pirates, since their mainland and maritime forces were occupied elsewhere. ... Not until the Arabs were stopped in 732 and driven from Gaul in 769, did they direct their main attacks upon mid-Europe, upon Italy and its neighboring islands."--'A History of the Crusades (1958)