Sibylline oracle texts and the divination deity Apollo associated with them experienced a very special form of history in Rome. One of the four highest Roman priesthoods, the quindecimviri sacris faciundis, was entrusted with their custody and consultation. Research has long attributed a close personal relationship to Apollon to the first Roman Emperor Augustus. The study examines the specific role played by Sibylline oracles and said god during the crisis of the late Roman Republic and the first decades of the Augustan Principate.