The Appian Way was used as a main route for military supplies since its construction for that purpose in 312 B.C.
The Appian Way was the first long road built specifically to transport troops outside the smaller region of greater Rome (this was essential to the Romans). The few roads outside the early city were Etruscan and went mainly to Etruria. By the late Republic, the Romans had expanded over most of Italy and were masters of road construction. Their roads began at Rome, where the master itinerarium, or list of destinations along the roads, was located, and extended to the borders of their domain — hence the expression, "All roads lead to Rome".
Romans had an affinity for the people of Campania, who, like themselves, traced their backgrounds to the Etruscans. The Samnite Wars were instigated by the Samnites when Rome attempted to ally itself with the city of Capua in Campania. The Italic speakers in Latium had long ago been subdued and incorporated into the Roman state. They were responsible for changing Rome from a primarily Etruscan to a primarily Italic state.
Dense populations of sovereign Samnites remained in the mountains north of Capua, which is just north of the Greek city of Neapolis. Around 343 BC, Rome and Capua attempted to form an alliance, a first step toward a closer unity. The Samnites reacted with military force.