The Italian term was used for a dictator, usually a profes-sional military man, who seized control of an independent Italian city, establishing authoritarian rule though in some cases preserving (while also controlling) the institutions of the previous republican system. Although most of the larger cities of northern and central Italy had gained their independence during the 12th and 13th cen-turies under republican constitutions, many of them accepted a sig-nore during the 13th and 14th centuries, sometimes seeking a de-fender against aggressive neighbors but more often seeking internal peace and stability after periods of violent conflict between rival po-litical factions. In most cases, the signore tried to stabilize his posi-tion by acquiring a traditional feudal title such as duke, marquis, or count, and also by transforming what often began as a personal au-thority into a dynastic lordship inheritable by his descendants. Ex-amples of such regimes were the Visconti (and later the Sforza) in Milan, the Este in Ferrara, and the Gonzaga in Mantua. Only rarely did a signore rise to power exclusively through military power. Most commonly, they used a combination of political manipulation and force, presenting themselves as protectors of the general interest against selfish factions among the wealthy citizens who traditionally dominated all Italian city-republics.
Some signori organized regimes that lasted for several centuries, while other such lordships collapsed during the lifetime of the founder and many more within a generation or two. By the 15th cen-tury, only two of the larger Italian republics, Venice and Florence, preserved their medieval republican constitutions relatively intact. Most Italian communes became signories. This development meant that despite the strongly republican spirit associated with early Paduan humanism and later with Florentine intellectual life during the early 15th century (a tendency often called "civic humanism"), the new humanistic learning, vernacular literature, and art of the Italian Renaissance proved readily adaptable to a monarchical political sys-tem. The Italian term for the rule of such a signore is signaría. The latter term was also used for the most powerful executive council of the republic of Florence, the Signaría.
Historical Dictionary of Renaissance. Charles G. Nauert. 2004.