"Genoese-Ottoman relations were based very firmly on mutual interest. The Genoese were essentially pragmatic in their dealings with the Turks, something which was no doubt encouraged by the fact that Genoese Turkish policy was largely dictated by the Genoese on the spot in colonies such as Pera and Chios rather than directed from Genoa itself. Even during the siege of Constantinople, the Genoese of Pera managed to maintain their relations with the Turks, while, simultaneously, siding with the defenders of the city, sending letters urgently requesting help to Genoa, ambassadors to the Sultan in Erdine to renew treaty relations and express undying friendship, soldiers to Constantinople, oil for Turkish cannons to the sultan's camp and betraying Longo Giustiniano's scheme to set fire to the Turkish ships. Relations were such that when Turkish cannon sank a ship belonging to Genoese merchants of Pera, loaded with merchandise and ready to leave for Italy, the Perotes complained to the Turks. Explaining that they had not realised that the ship belonged to the Genoese of Pera, taking it rather as belonging to the enemy, the Turks assured them that, after the capture of the city, the merchants would be fully indemnified."

- European and Islamic Trade in the Early Ottoman State: The Merchants of Genoa and Turkey, Kate Fleet, p. 127-8

Gah.