vestal (vĕs`təl), in Roman religion, priestess of Vesta. The vestals were first two, then four, then six in number. While still little girls, they were chosen from prominent Roman families to serve for 30 (originally 5) years, during which time they could not marry. Their duties included the preparation of sacrifices and the tending of the sacred fire. If any vestal broke her vow of chastity, she was entombed alive. The vestals had great influence in the Roman state.