 In 1256–1259 he, already lifted from the excommunication, helped Pope Alexander IV and Treviso in the war for the Marca Trevigiana against the Ghibelline warlord Ezzelino IV da Romano, whose death resolved the conflict.In the meantime, Venice found itself engaged in a war against the Republic of Genoa, its greatest rival in the Mediterranean.The cause of the conflict was the sacking by the Genoese of the Venetian quarter in Tyre.