Podestà is the name given to certain high officials in many Italian cities, since the later Middle Ages, mainly as Chief magistrate of a city state (like otherwise styled counterparts in other cities, e.g. rettori "rectors"), but also as a local administrator, the representative of the (Holy Roman) Emperor.
The term derives from the Latin word potestas, meaning power. This development of a term meaning "Power" or "Authority" to be eventually the title of the person holding such power is parallel to the development of the Islamic term "Sultan".
The first documented usage of podestà was in Bologna in 1151, when it was applied to Guido di Ranieri di Sasso of Canossa, brought in from Faenza to be rettore e podestà, noted in numerous documents. Leander Albertus gives the particulars:
The citizens, seeing that there often arose among them quarrels and altercations, whether from favoritism or friendship, from envy or hatred that one had against another, by which their republic suffered great harm, loss and detriment; therefore, they decided, after much deliberation, to provide against these disorders. And thus they began to create a man of foreign birth their chief magistrate, giving him every power, authority and jurisdiction over the city, as well over criminal as over civil causes, and in times of war as well as in times of peace, calling him praetor as being above the others, or podestà., as having every authority and power over the city."