Quaestor, the title of a Roman magistrate, whose chief duty, in the later days of the Republic, was the superintendence of the public treasury. It ranked lowest among the great magistracies, and was consequently held by all politicians at the outset of their career. After 421 B.C. plebeians were eligible for the office. In the same year two new quaestors were added to the original couple. The number was increased to eight about 267 B.C., and to 20 in 81 B.C. The quaestors held office for one year, but when it became customary for the consul (or praetor) to be granted a province as proconsul (or propraetor) after the expiration of his term, the quaestor also retained his position with the title of proquaestor.