The Apennines are the chain of mountains that form the backbone of Italy. They were an important economic resource in antiquity, particularly supporting the rearing of sheep, goats, and pigs. Although not impenetrable, the Apennines did hinder East-West communications in prehistory and, consequently, helped shape the differing trajectories of cultural development in Tyrrhenian and Adriatic Italy. The few low-lying crossing points were also strategically important in ancient times.
Bagnall, R.S., Brodersen, K., Champion, C.G., Erskine, A. & Huebner, S.R.