sentences:  Less than eight years from his accession, William had extended his power to Lanzo and the vicinity of Alessandria.Though aided immensely by the Angevins, the lords of Montferrat had never been known for loyalty to a cause or party and William was no different, abandoning Charles soon after his success, probably fearful of the king's rising power in northern Italy and of being encircled by an Angevin state.William allied with Alfonso X of Castile, who had declared himself the heir of Manfred of Sicily and therefore of the Emperor Frederick II, as the leaders of an anti-Angevin coalition.