The heir of a rich fund of capital, and enriched further after lending huge amounts of money to Pope Alexander VI (and to other rulers of the time as well), he strayed from common mercantile practice by obtaining lucrative monopolies like the salt monopoly of the Papal States and the Kingdom of Naples, as well as that of the alum excavated in Tolfa,[3] Agnato and Ischia di Castro.

[4] Agostino established economic ties with the whole of Western Europe, at one time having up to 20,000 employees, receiving from Siena the title of Il Magnifico ("Magnificent").

[5] Chigi, "indisputably the richest man in Rome",[6] became also a rich patron of art and literature, the protector of Pietro Aretino among others, though his own education suffered many lacunae, notably his lack of Latin.

[8] His artistic protégés included almost all the main figures of the early 16th century: Perugino (from whom he commissioned the eponymous Chigi Altarpiece), Sebastiano del Piombo, Giovanni da Udine, Giulio Romano, Sodoma and Raphael.

In order to show his contempt of money, he was said to have all the silver dishes thrown into the river after the end of the parties; however, his servants were secretly ready to recollect them with nets draped under the windows.