Genoa had acquired a largely dominant position in the markets of southern France. The war presumably began in 1165 on the Rhône, when an attack on a convoy, directed to some Pisan trade centres on the river, by the Genoese and their ally, the count of Toulouse, failed. Pisa, though, was allied to Provence. The war continued until 1175 without significant victories. Another point of attrition was Sicily, where both the cities had privileges granted by Henry VI. In 1192, Pisa managed to conquer Messina. This episode was followed by a series of battles culminating in the Genoese conquest of Syracuse in 1204. Later, the trading posts in Sicily were lost when the new Pope Innocent III, though removing the excommunication cast over Pisa by his predecessor Celestine III, allied himself with the Guelph League of Tuscany, led by Florence. Soon, he stipulated a pact with Genoa, too, further weakening the Pisan presence in southern Italy.