Under the year 1035 (Pisan style) Marangone records a new expedition, undertaken by the Pisans alone against the Saracens of Africa: “Pisani fecerunt stolum in Africam ad civitatem Bonam; gratia Dei vicerunt illos.” Later chroniclers added the conquest of Carthage to that of Bona and asserted that the victors sent the crown of the Moslem king (afterwards confused with Mogahid) to the Emperor Conrad; while, finally, we are told that “in the year of our Lord one thousand and thirty-five, the Pisans took the Lipari Islands by force of arms and gave them to the Emperor of Rome, and thereafter for a time they rested.”

The substratum of truth which underlies these fables is to be found in an expedition against Moezz-ibn-Badis, a powerful prince of the Zirite dynasty, who had built a fleet of warships at Mehdia (Almedia, Mahdiya) with which he infested the Mediterranean. There seems to have been a naval engagement in the neighbourhood of Bona, which was subsequently sacked by the victors. Amari infers from an obscure passage in the chronicle of Rudolf the Bald that besides the Pisans there were Provencals and Genoese who took part in the battle.