In Roman times it was situated on the northern slopes of the hills Coressus and Pion and south of the Cayster (Küçükmenderes) River, the silt from which has since formed a fertile plain but has caused the coastline to move ever farther west. The Temple of Artemis, or Diana, to which Ephesus owed much of its fame and which seems to mark the site of the classical Greek city, was probably on the seaboard when it was founded (about 600 BCE), one mile east by northeast of Pion (modern Panayir Daǧ). In Roman times a sea channel was maintained with difficulty to a harbour well west of Pion. By late Byzantine times this channel had become useless, and the coast by the mid-20th century was three miles farther west. Ephesus commanded the west end of one great trade route into Asia, that along the Cayster valley, and had easy access to the other two, along the Hermus (Gediz) and the Maeander (Büyükmenderes) river