Why were the apennine mountains important to rome?

The Apennine Mountains prove to be a vital member of the Italian geography. This boundary not only culturally separated the East and West Lowland areas, but also provided a huge barrier to attack. If Italy was ever attacked from one side, it would be able to build enough forces on the other side of the mountains in time to counter the opposing force. This natural layout prevented any swift attacks from either the Adriatic or the Tyrrhenian Seas.