in increased the rivalry with Genoa. Pisa's trade with the Languedoc and Provence (Noli, Savona, Fréjus and Montpellier) were an obstacle to the Genoese interests in cities like Hyères, Fos, Antibes and Marseille.
The war began in 1119 when the Genoese attacked several galleys on their way to the motherland, and lasted until 1133. The two cities fought each other on land and at sea, but hostilities were limited to raids and pirate-like assaults.
In June 1135, Bernard of Clairvaux took a leading part in the Council of Pisa, asserting the claims of pope Innocent II against those of pope Anacletus II, who had been elected pope in 1130 with Norman support but was not recognised outside Rome. Innocent II resolved the conflict with Genoa, establishing the sphere of influence of Pisa and Genoa. Pisa could then, unhindered by Genoa, participate in the conflict of Innocent II against king Roger II of Sicily. Amalfi, one of the Maritime Republics (though already declining under Norman rule), was conquered on 6 August 1136: the Pisans destroyed the ships in the port, assaulted the castles in the surrounding areas and drove back an army sent by Roger from Aversa. This victory brought Pisa to the peak of its power and to a standing equal to Venice. Two years later its soldiers sacked Salerno.
In the following years Pisa was one of the staunchest supporters of the Ghibelline party. This was much appreciated by Frederick I. He issued in 1162 and 1165 two important documents, with the following grants: apart from the jurisdiction over the Pisan countryside, the Pisans were granted freedom of trade in the whole Empire, the coast from Civitavecchia to Portovenere, a half of Palermo, Messina, Salerno and Naples, the whole of Gaeta, Mazara and Trapani, and a street with houses for its merchants in every city of the Kingdom of Sicily. Some of these grants were later confirmed by Henry VI, Otto IV and Frederick II. They marked the apex of Pisa's power, but also
