"first on the banks of Hebrus didst produce"
Origin of the Maritsa river, Bulgaria
Public DomainOrigin of the Maritsa river, Bulgaria - Credit: Preslav

The Maritsa or Evros river was known in ancient times as the Hebrus.  It runs for 480km, across the Balkan interior.  It originates in the Rila Mountains in Western Bulgaria, and flows southeast between the Balkan and Rhodope Mountains, to Turkey.  It forms a border between Bulgaria and Greece, and between Turkey and Greece.