An official elected in many Italian communes of the 13th and 14th centuries, normally acting as the chief executive of the combined local guilds in opposition to the old patrician families that dominated the government of most cities in the early period of the independent communes. The capitano del popolo assumed a mediating role in relations between various guilds, acquired informal extralegal powers in order to restrain the disfranchised noble clans (the grandi), and in many places ended by becoming the signore, or dictator, of the city. Examples of the ascension of capitani del popolo to hereditary rule include the Carrara dynasty at Padua, the della Scala at Verona, the Gonzaga at Mantua, and the Della Torre and Visconti families at Milan. At Florence, however, which was exceptional in its successful resistance to the rise of a dictatorship, the power of the capitano was restrained by a requirement to have his decrees ratified by a council of citizens.
Historical Dictionary of Renaissance. Charles G. Nauert. 2004.