Sibyllæ (si-bil ´), or Sibyls .—Prophetesses, supposed to be ten in number. The most famous of them is the Cumæan, who was consulted by Æneas before he descended into the lower world and gave him the sop to throw to Cerberus, which, when he had devoured it, threw him into a deep sleep and so enabled Æneas to slip by.