She was one of the women taken hostage by Lars Porsena as a part of the peace treaty which ended the war between Rome and Clusium in 508 BC.
According to Valerius Maximus, she fled upon a horse, and swam across the river Tiber through a barrage of hostile darts, thus bringing her band of girls to safety.
He declared to the Romans that if she were restored to him he would send her back to Rome safe and inviolate, but if his demands were not met he should regard the treaty as broken.
Porsena praised Cloelia on her arrival and, as a reward for her heroism, promised to release half the share of his hostages of her choice.
[3] Once peace had been established, the Romans celebrated her valour by building a statue of a maiden seated on a horse, set up on the summit of the Via Sacra.