During the twelfth century, the Mediterranean Sea contained a complex array of economic, political, military, religious, and social networks. My dissertation explores the relationship of two dynasties that were at the center of these networks: the Norman lords of Sicily and the Zirid emirs of Ifriqiya (roughly modern-day Tunisia, eastern Algeria, and western Libya) in the years leading up to the Norman conquest of Zirid lands and the formation of the Norman Kingdom of Africa (1148-1160). Previous scholarship, particularly work written by French colonial historians, has emphasized the triumph of the Christian Normans over their Muslim foes and disregarded the agency of the Zirids. I show that the medieval sources tell a different story. Latin and Arabic texts attest to the importance of the Zirid emirs of Ifriqiya to larger networks in the Mediterranean. In 1123, for example, the Zirid emir al-Hasan ibn ‘Ali united a group of Arab and Berber (indigenous North African) tribes to defeat the navy of the Norman lord Roger II. Several years later, al-Hasan ibn ‘Ali formed an alliance with the Almoravids of Morocco to raid cities along the coast of Sicily. Zirid power in Ifriqiya only waned in the wake of a decade-long drought, which allowed the opportunistic Normans to seize Zirid lands. The Normans under Roger II and his son William I ruled the coastline of Ifriqiya for twelve years, during which time they made small changes to its society that favored Christians over Muslims while occasionally proclaiming themselves “King of Africa.” Arabic chroniclers writing about the Norman conquest of Ifriqiya did not acknowledge the legitimacy of the Normans’ kingship in Ifriqiya and instead presented the Normans as one prong of a Mediterranean-wide “Frankish” assault upon the lands of Islam, one that warranted jihad on all fronts.