The ‘black death’ had hardly run its course in Italy when the commercial rivalries of Genoa and Venice culminated in a bitter war, that lasted for two years, with varying fortunes, until the battle of Lojera in 1353 broke the sea-power of Genoa. After five centuries of independence the Genoese were compelled to put themselves under the protection of Milan. The hatred engendered by this struggle is revealed in the archives of the two republics. They left unturned no stone to destroy each other. The history of Venice and Genoa during the fourteenth century reads like that of Sparta and Athens. The scene of the conflict is the same: the motive, the spirit, and the result are identical. Venice gained no material advantage from the war. She had long been alive to the menace of the Osmanlis.[208] She had been warned by Petrarch of the certain danger which a war with Genoa would entail, whether its outcome were favourable or unfavourable.[209] The Ottoman and Byzantine historians are silent concerning the relations of the Osmanlis with the Genoese during this war. That the Genoese asked for and received aid from Orkhan is certain. There had been a convention beforehand between the Osmanlis and the Genoese of Pera.[210] Both against the Greeks and against the Venetians the assistance of Orkhan must have been substantial.[211] It was remembered with gratitude forty years later.[212] The triumphal entry into Constantinople and the sanction of the Church upon his imperial office did not end the troubles of Cantacuzenos. The first to turn against him was his own son Matthew, who also wanted to be emperor. Cantacuzenos appeased him for a time by giving him a portion of Thrace. Then the Genoese of Pera, dissatisfied with the lowering of the customs tariff to other nations, burned the Greek galleys and arsenals, and attacked Constantinople. Cantacuzenos had to leave a sick-bed at Demotika to hurry to save the city. The Greek fleet was destroyed by the Genoese. The army of Cantacuzenos failed in an attack upon Galata. Peace was concluded only when the unhappy emperor agreed to sell more land on the Golden Horn to the Genoese, and restore them in the customs tariffs to their former place as ‘most favoured nation’.[213]