Wikipedia
In the theatre of ancient Greece, the chorêgos (pl. chorêgoi; , Greek etymology: χορός "chorus" + ἡγεῖσθαι "to lead") was a wealthy Athenian citizen who assumed the public duty, or choregiai, of financing the preparation for the chorus and other aspects of dramatic production that were not paid for by the government of the polis or city-state. Modern Anglicized forms of the word include choragus and choregus, with the accepted plurals being the Latin forms choregi and choragi. In modern Greek the word χορηγός is synonymous with the word "grantor".
Choregoi were appointed by the archon and the tribes of Athenian citizens from among the Athenian citizens of great wealth. Service as a choregos, though an honor, was a duty for wealthy citizens and was part of the liturgical system designed to improve the city-state's economic stability through the use of private wealth to fund public good. Choregoi paid for costumes, rehearsals, expenses of the chorus (including training, salaries, board and lodging), scenery, props (including elaborate masks), special effects and most of the musicians. The choregos also hosted a feast if his chorus proved victorious in competition. The prizes for drama at the Athenian festival competitions were awarded jointly to the playwright and the choregos. Such victories carried prestige for the choregos. Several notable political figures served as choregoi, including Themistocles, Pericles and Plato, among others. Monuments were built in honor of victorious choregoi.
At the turn of the 17th century AD, in an attempt to recreate the ancient Greek dramatic tradition, the position was revived briefly in Italian opera, and combined the roles of impresario and director.