Shadow Diplomacy: Pisa, Denia, and a Lost Muslim-Christian Alliance in the Eleventh-Century Mediterranean

This article combines a close reading of primary sources with speculation and circumstantial evidence to explore the possibility of an undocumented military alliance between Pisa, Denia, and possibly the Banu Hammad. Building on earlier scholarship, it posits that connections formed during the Sardinian War of 1015-1016 led to ongoing diplomatic or military links between the principals, aimed at countering the power of the Zirid dynasty of Tunisia and Granada. This military alliance (if it existed) fell out of Pisan historical consciousness in the twelfth century due to disputes between Pisa and Genoa over the historical justifications for their hegemony in Sardinia.