In ancient Rome, the quindecimviri sacris faciundis were the fifteen (quindecim) members of a college (collegium) with priestly duties. They guarded the Sibylline Books,[1][2][3] scriptures which they consulted and interpreted at the request of the Senate.[4] This collegium also oversaw the worship of any foreign gods which were introduced to Rome. They were also responsible for responding to divine advice and omens.[5]
Originally these duties had been performed by duumviri (or duoviri), two men of patrician status.[6][7] Their number was increased to ten by the Licinian-Sextian Law in 367 BC, which also required for half of the priests to be plebeian. During the Middle Republic, members of the college were admitted through co-option. Sulla increased the number of priests to fifteen.[8] The Lex Domitia removed their ability to select their own members in 104 BCE. Afterwards candidates from wealthy Roman gentes would be elected.[9]
At some point in the third century BC, several priesthoods, probably including the quindecimviri, began to be elected through the voting tribes.[10]