The historiography of OƩoman commercial relaƟons has oŌen represented OƩoman rulers as unilateral grantors of privileges to foreign powers and their merchants, especially through the language of “privileges” and “capitulaƟons”. This thesis argues that this interpretaƟon does not adequately describe OƩoman foreign trade policy in the second half of the fiŌeenth century. To demonstrate this, it combines a historiographical reassessment of the categories used to describe OƩoman diplomaƟc instruments with an empirical analysis of the available dated treaƟes concluded with LaƟn powers and the dated OƩoman customs laws of the same period. This approach makes it possible to disƟnguish between reciprocity in diplomaƟc agreements and fiscal differenƟaƟon within the OƩoman customs regime. Rather than revealing a regime of one-way concession, the analysis shows that the treaƟes were negoƟated arrangements which secured corresponding commercial rights for OƩoman merchants in the counterparƟes’ territories. At the same Ɵme, the customs laws placed LaƟn merchants at a fiscal disadvantage compared with OƩoman subjects, especially OƩoman Muslims. Read together, treaƟes and customs regulaƟons show that commercial access did not necessarily amount to favourable fiscal treatment, and they illuminate how OƩoman foreign trade policy was formulated and implemented in the second half of the fiŌeenth century. This thesis thus contributes to a broader reassessment of OƩoman economic policy by presenƟng OƩoman rulers of this period not as passive dispensers of concessions, but as acƟve parƟcipants in the poliƟcal economy of Mediterranean trade.