What physical characteristics made the Italian peninsula an ideal location to establish settlements? How did these early settlements interact with each other?

The most important physical characteristics are:

1. access to the sea: the Mediterranean Sea was offering them the position of natural harbors for the ships, good trade routes and access to fish, which became the main source of their nutrition

2. the Alps represented the natural barrier between Italy and its neighbors, so they could avoid any outside attacks

3. the position of the peninsula provided to the Italian settlements the favorable climate with mild winters and hot summers. Therefore, the settlements were able to develop strong agriculture and grow grapes, olives, and wheat.

They had mainly economic and social interactions at the markets, where people were able to sell their goods, like fish, grapes, wealth, manufacturing products, etc.