An ancient ford of the river in the territory of Colli del Tronto (AP) allowed an easy north to south access.  This was an meeting point between the peoples that inhabited the two banks of the river. They were similar on many aspects, but different.  They spoke languages that were similar but not identical.

On this border, a bride from the south had met her husband, man of the north. Her remains were found in a tomb at Colle Vaccaro near the top of the hill that is inhabited even today. Her tomb was covered in river pebbles exactly like it was customary in northern Abruzzo back then; on the contrary, all the others, about thirty, were closed with yellowish earth.

The river was most certainly navigable from the delta to this point, and it was frontier and meeting point at the same time.