 The kingdom was soon increasingly dominated by the Italian city-states of Venice and Genoa, as well as the imperial ambitions of the Holy Roman Emperors.Emperor Frederick II (reigned 1220-1250) claimed the kingdom by marriage, but his presence sparked a civil war (1228-1243) among the kingdom's nobility.The kingdom became little more than a pawn in the politics and warfare of the Ayyubid and Mamluk dynasties in Egypt, as well as the Khwarezmian and Mongol invaders.