A Praetor was a title granted by the Roman senate to one holding the magistrate rank inferior only to censors and consuls. Praetors commanded armies in the absence of the consuls and, more routinely, served as the judges of the Roman Republic. By the time of the Third Servile War, eight praetors were elected every year for a one-year term.
A Roman citizen had to be at least 39 years old to be elected praetor, and to have previously served at least one term as a quaestor. After a one-year term, praetors were routinely made propraetors by the Senate to serve as governors of territories outside Terra Italia.
This was an opportunity for great plunder, either by conquest of enemies on the frontiers of those territories, or by political extortion of the subject population. Service as praetor therefore became the crucial launching pad of political careers of those who lacked independent wealth to cultivate political alliances and develop the broad clientele necessary to achieve the highest political offices.
Originally Praetors were the two magistrates created to replace the function of the deposed king, so called because they preceded before all other magistrates. Later as the Republic grew two more were created, the Praetor Urbanus who ran the city and the Praetor Peregrinus who dealt with matters involving non-citizens. When these offices were created the first praetors became known as Consuls. As the Republic grew further additional praetors were appointed to govern the newly acquired provinces. The Emperors substituted legates they appointed in place of the praetors as provincial governors, except with respect to the province of Africa. The Urban and Foreign Praetors retained their functions, but became Imperial appointees and were further reduced in authority by the creation of the praetorian guard and vigiles, both of whom was commanded by a prefect who reported to the Emperor. The Urban Cohorts were commanded by the Urban Praetor, who under the Empire functioned more or less as the mayor of Rome.