Clement VII's tumultuous pontificate was dominated by a rapid succession of political crises—many long in the making—that resulted in the sack of Rome by the armies of Holy Roman Emperor Charles V in 1527 and rise of the Salviati, Altoviti and Strozzi as the leading bankers of the Roman Curie. From the time of Clement's election as pope in 1523 until the sack of Rome, Florence was governed by the young Ippolito de' Medici (future cardinal and vice-chancellor of the Holy Roman Church), Alessandro de' Medici (future duke of Florence), and their guardians. In 1530, after allying himself with Charles V, Pope Clement VII succeeded in securing the engagement of Charles V's daughter Margeret of Austria to his illegitimate nephew (reputedly his son) Alessandro de' Medici. Clement also convinced Charles V to name Alessandro as Duke of Florence. Thus began the reign of Medici monarchs in Florence, which lasted two centuries.