The circle of the world: the global diplomacy of Caliph al-Manṣūr

Abstract Between 757 and 768, the second ʿAbbāsid caliph, al-Manṣūr, engaged in an unprecedented set of foreign relations which stretched across Afro-Eurasia, from Tang China to Carolingian Francia. The unique scale of this activity has previously gone unnoticed because much of the evidence comes from the caliph’s diplomatic partners. Al-Manṣūr’s dealings with these polities tend to be taken on a case-by-case basis, resulting in often-unconvincing explanations of his motives. By instead taking all of this activity together as a whole, we can see a deliberate policy of “prestige diplomacy”, in which the caliph sought to legitimize his regime to a domestic audience by bringing envoys and gifts to his court, following Sasanian models of universal kingship.