Between Material Prosperity and Loyalty to Ideological Doctrine: The Forbidden Trade in the Era of the Crusades (1096-1291 AD)

Abstract

The present article examines the policy of prohibiting the trade of war goods between Christians and the Islamic East, and between Muslims and the European West, during the Crusades (5th-7th centuries AH / 11th-13th centuries AD). This policy is primarily documented in Vatican records for the European West and in Islamic jurisprudence for the Muslim world. Despite the ban, merchants were more focused on commerce, often disregarding the consequences of their actions. In response, the Church intensified its support for the Crusades by convening councils where the issue of trading strategic goods with Muslims was addressed. The Church imposed excommunication on those who sold essential war materials to Muslims, and this prohibition was repeatedly renewed. The banned items included metals, timber (especially long wood, which was scarce in the region and crucial for shipbuilding), tar, weapons, sulfur, and horses. Even food and livestock could be subject to the ban. This article argues that merchants frequently defied these restrictions, continuing to trade in strategic war goods, which highlights the challenges faced by authorities in enforcing papal decrees.