On the 17th of May, 1165, just one month after Frederick had annulled the investiture of Barisone of Arborea and granted Sardinia to Pisa, there was a sea-fight between the Pisans and Genoese in the Bay of Porto Venere. In the previous February news had reached Genoa that a Genoese merchantman returning from Ceuta had been shipwrecked off Asinara and captured by the Pisans. The truce between the Communes was still nominally in force, and ambassadors were forthwith sent to the Emperor, “conquerentes de treugua quam Pisani fregerant.” The adjustment of the matter was entrusted to Conrad, Frederick's chaplain, and the representatives of Pisa and Genoa met in the island of Palmaria. A long and acrimonious debate followed, and, unfortunately, when the exasperation of both parties was at its height, the galley of the notorious corsair Trapilicini entered the Bay of Porto Venere. Formerly a Pisan subject, Trapilicini was now in the service of Genoa, and the Pisans would have given a good deal to lay their hands on him. The Genoese Consul seems to have endeavoured to pour oil on the troubled waters, but he received no assistance from Trapilicini himself who told the Pisans to their faces that he was setting out “pro capiendis vestris et vestrorum rebus et personis, et pro nasis obtruncandis vestratum, nisi cum consule Ianue concordiam feceritis.”