Bills of exchange, interest bans, and impersonal exchange in Islam and Christianity

A vast economic history literature suggests that medieval institutions supporting contract enforcement were necessary for impersonal exchange to emerge. Yet this literature cannot account for the bill of exchange, an important financial instrument that had positive legal standing in both the medieval Islamic and Christian worlds but remained relegated to personal networks only in the former. This paper suggests that a seemingly innocuous difference - the involvement of currency exchange in European but not Middle Eastern bills, a difference resulting from the secular legalization of interest in Europe - encouraged divergent endogenous processes resulting in these distinct institutional arrangements.