​CREMERA (mod. Fosso della Valchetta), a small stream in Etruria which falls into the Tiber about 6 m. N. of Rome. The identification with the Fosso della Valchetta is fixed as correct by the account in Livy ii. 49, which shows that the Saxa Rubra were not far off, and this we know to be the Roman name of the post station of Prima Porta, about 7 m. from Rome on the Via Flaminia. It is famous for the defeat of the three hundred Fabii, who had established a fortified post on its banks.