On 4 June 1055 Pope Victor II held a major synod in Florence, attended by Henry III and 120 bishops, at which King Ferdinand of Spain was threatened with excommunication if he did not swear allegiance to Henry. Ferdinand submitted.
Henry was mainly concerned at the synod in breaking up the dangerous alliance of Lorraine and Tuscany against his rule. The allegiance of Ferdinand was just part of a package of measures he needed to keep his empire together.
In those days Pope Victor II held a council at Florence, and the Emperor Henry there made his complaint against King Don Ferrando, that he did not acknowledge his sovereignty, and pay him tribute like all other Kings; and he besought the Pope to admonish him so to do.