but she that has broken her vow is buried alive near the gate called Collina, where a little mound of earth stands, inside the city, reaching some little distance, called in Latin agger; under it a narrow room is constructed, to which a descent is made by stairs; here they prepare a bed, and light a lamp, and leave a small quantity of victuals, such as bread, water, a pail of milk, and some oil; that so that body which had been consecrated and devoted to the most sacred service of religion might not be said to perish by such a death as famine. The culprit herself is put in a litter, which they cover over, and tie her down with cords on it, so that nothing she utters may be heard. They then take her to the forum; all people silently go out of the way as she passes, and such as follow accompany the bier with solemn and speechless sorrow; and, indeed, there is not any spectacle more appalling, nor any day observed by the city with greater appearance of gloom and sadness. When they come to the place of execution, the officers loose the cords, and then the high priest, lifting his hands to heaven, pronounces certain prayers to himself before the act; then he brings out the prisoner, being still covered, and placing her upon the steps that lead down to the cell, turns away his face with the rest of the priests; the stairs are drawn up after she has gone down, and a quantity of earth is heaped up over the entrance to the cell, so as to prevent it from being distinguished from the rest of the mound. This is the punishment of those who break their vow of virginity.
Plutarchus’ description of the punishment for Vestal Virgins who broke their vow of virginity