The annihilation of the Senones had given to the Romans a considerable tract of the Adriatic coast.

With a view, doubtless, to the smouldering feud with Tarentum and the already threatened invasion of the Epirots, they hastened to make themselves sure of this coast as well as of the Adriatic sea.

A burgess colony was sent out (about 471) to the seaport of Sena (Sinigaglia), the former capital of the Senonian territory; and at the same time a Roman fleet sailed from the Tyrrhene sea into the eastern waters, manifestly for the purpose of being stationed in the Adriatic and of protecting the Roman possessions there.
Breach between Rome and Tarentum The Tarentines since the treaty of 450 had lived at peace with Rome.
They had been spectators of the long struggle of the Samnites, and of the rapid extirpation of the Senones; they had acquiesced without remonstrance in the establishment of Venusia, Atria, and Sena, and in the occupation of Thurii and of Rhegium.

But when the Roman fleet, on its voyage from the Tyrrhene to the Adriatic sea, now arrived in the Tarentine waters and cast anchor in the harbour of the friendly city, the long, cherished resentment at length overflowed.

Old treaties, which prohibited the war-vessels of Rome from sailing to the east of the Lacinian promontory, were appealed to by popular orators in the assembly of the citizens.