The Silva Ciminia, the Ciminian Forest, was the unbroken primeval forest that separated Ancient Rome from Etruria. According to the Roman historian Livy it was, in the 4th century BCE, a feared, pathless wilderness in which few dared tread. The Ciminian Forest received its name from the Monti Cimini, which are still a densely wooded range of volcanic hills northwest of Rome. They form the part of the forerange of the Apennine main range that faces towards the Tyrrhenian Sea.