The many disputes, even the armed ones, were set aside in 1087 when they reunited to fight their common enemy. In the summer of the same year, a massive fleet composed of two hundred galleys from Genoa and Pisa, with some from Gaeta, Salerno and Amalfi, set sail for the Mediterranean coast of Africa. The fleet mounted a successful offensive against Mahdia on 6 August 1087. On 21 April 1092 the Pope elevated the archdiocese of Pisa to the rank of metropolitan archdiocese and placed the bishops of Corsica under its authority.