Sibylline Books
According to one story, Tarquin was approached by the Cumaean Sibyl, who offered him nine books of prophecy at an exorbitant price. Tarquin abruptly refused, and the Sibyl proceeded to burn three of the nine. She then offered him the remaining books, but at the same price. He hesitated, but refused again. The Sibyl then burned three more books before offering him the three remaining books at the original price. At last Tarquin accepted, in this way obtaining the Sibylline Books.