One of the most important examples of Muslim vassalage to Christian kings in twelfth-century Iberia is that of Sayf al-Dawla Ahmad al-Mustansir billah, a descendant of the royal line of the Banu Hud, who was one of the clients of Alfonso VII (r. 1126–1157). In this paper, I propose to re-examine the dynamics of the relationship which existed between Sayf al-Dawla and Alfonso VII as represented by one particular text, the Chronica Adefonsi Imperatoris. Although I will also bring other texts into conversation with the representation of Sayf al-Dawla provided by the chronicle, I am primarily concerned with explaining how the CAI seeks to construct an image of Alfonso VII as imperator totius hispaniae, emperor of Iberia, through its discussion of the Leonese monarch’s relationship with this Muslim prince. Moreover, I hope to shed important light on the nature of the relationship between Alfonso VII and Sayf al-Dawla, especially as constructed by the chronicle. Throughout the text, Sayf al-Dawla plays a prominent role as a member of Alfonso’s court, war council, and is often present on the campaigns of the king into Andalusia. His role as an intermediary between Alfonso VII and the Andalusian princes living under Almoravid rule is also highlighted throughout the text, and he emerges as an essential figure in the development of Alfonso’s policies towards al-Andalus. More notably, Sayf al-Dawla is identified in the text itself by Alfonso VII as his “friend,” a proclamation which simultaneously highlights the relationship between the two sovereigns and the unique dynamic of Muslim-Christian interaction in the Iberian peninsula during the twelfth century.