Rome was located in central Italy and built on seven hills along the Tiber River. Over time, the Roman Empire expanded across the Italian peninsula and eventually spanned Spain, northern Africa, Asia Minor, Gaul, and other regions. The Punic Wars were a series of conflicts between Rome and Carthage that resulted in Rome gaining control of territories like Sicily and Spain. Barbarian invasions in the late empire led to the decline of Roman authority in places like Greece and Gaul.