Fighting for the Enemy: The Mercenary between Christianity and Islam

Barack Obama does not demand a Muslim-only Secret Service, nor does Mahmoud Ahmadinejad insist upon an exclusively Christian bodyguard. During the medieval and early modern periods, however, Muslim and Christian rulers regularly hired mercenary guards of each other’s faith to defend their persons and bolster their armies. In a time famous for its religious antagonism, these mercenary bands crossed a confessional divide, spread through the Mediterranean, and carved out a presence for themselves in their host societies, sometimes for centuries. While they often fought against members of each other’s faith, they sometimes took up arms against their co-religionists as well. Even so, they operated with the tacit consent, and sometimes much more, of their own religious and political authorities. In this paper, I seek to explain why, in the foundational era of crusade and jihad, rulers entrusted their lives and fortunes to adherents of an enemy faith, soldiers entered the service of their religious rivals, and home and host societies alike tolerated these betrayals of spiritual allegiance.
My investigation will be comparative. I will set the history of Muslim mercenaries in the Christian world alongside that of Christian mercenaries in the Islamic world, while placing both in the context of pre-modern Mediterranean interfaith relations more generally. To lend precision to my analysis, I will focus on the two regions where the guards were most commonly employed, the Iberian Peninsula and North Africa. The guards were not an exclusively western Mediterranean phenomenon, but it is there that they survived longest and left behind the richest evidence.