The only imperial coronation in medieval Spain, which took place in León in 1135, provides the basis for a comparative analysis of political languages in Christian and Islamic Spain, putting various imperial claims into the context of the political culture of the wider Mediterranean world. The changing use of both Christian and Muslim imperial titles reflects claims to regional hegemony at the periphery of the large oriental power blocks which existed in the Mediterranean until the 12th century. Christian and Muslim monarchs in Spain were not only reacting to rival rulers of the same religion when they adopted or usurped imperial titles, they were also looking at rulers of the other monotheistic religion. The imperial coronation of 1135 took place immediately after the renewed establishment of a second Muslim caliphate in the Muslim West by the Almohads, which, in return, can be understood as the expression of the Almohads’ fight for supremacy in Western Islam against the Almoravids. The latter, in turn, had derived their imperial claims from the caliph in Baghdad, while also rejecting imperial claims to overlordship by the Castilian king, who called himself “emperor of both religions”. Between the 10th and 12th centuries, the changing use of imperial titles by Christian and Muslim rulers was the expression of a competitive principle in which the entanglement of Christian and Islamic Spain became manifest.