The business of human trafficking: slaves and money between Western Italy and the House of Islam before the crusades (c.900–c.1100)

Before the First Crusade, the maritime cities of Italy imported precious objects from Islamic regions. The question of what they exported in return has long occupied historians. Due to the large economic disparity between Latin Italy and the wealthier House of Islam, human trafficking offered a strong profit opportunity to merchants from Amalfi, Pisa and other ports. This was because the price of a slave in Egypt or North Africa, at around 20 gold dinars, represented a large sum in the silver currency zones of Latin Europe, especially compared to low prices in Italy. Even moderate numbers of trafficked humans may therefore have provided the capital for further maritime economic expansion. Moreover, slaves offered a commodity with low infrastructure and transportation requirements, unlike bulk agricultural products, as well as unique advantages in market access, which suggests that slave trading preceded investment in other branches of commerce.