Archaeological evidence seems to confirm that all trade with the interior followed the foundation of Histria. Traders reached the interior via Histria and the Danube valley, demonstrated by finds of Attic black-figure pottery, coins, ornamental objects, an Ionian lebes and many fragments of amphoras. Amphoras have been found in great quantity at Histria, some imported but some local. Local pottery was produced following establishment of the colony and certainly before mid-6th century. During the archaic and classical periods, when Histria flourished, it was situated near fertile arable land. It served as a port of trade soon after its establishment, with fishing and agriculture as additional sources of income. By 100 AD, however, fishing was almost the sole remaining source of Istrian revenue.

(http://en.wikipedia.org/wiki/Histria_%28ancient_city%29)