In the last centuries BC, the Mediomatrici settled in the Saarbr�cken area. When Julius Caesar conquered Gaul in the 1st century BC, the area was incorporated into the Roman Empire.
From the 1st century AD to the 5th century, there was the Gallo-Roman settlement called vicus Saravus west of Saarbr�cken's Halberg hill, on the roads from Metz to Worms and from Trier to Stra�burg. Since the 1st or 2nd century AD, a wooden bridge, later upgraded to stone, connected vicus Saravus with the south-western bank of the Saar, today's St Arnual, where at least one Roman villa was located. In the 3rd century AD, a Mithras shrine was built in a cave in Halberg hill, on the eastern bank of the Saar river, next to today's old 'Osthafen' harbor, and a small Roman camp was constructed at the foot of Halberg hill next to the river.
Towards the end of the 4th century, the Alemanni destroyed the castra and vicus Saravus, removing permanent human presence from the Saarbr�cken area for almost a century.
The Saar area came under the control of the Franks towards the end of the 5th century. In the 6th century, the Merovingians gave the village Merkingen, which had formed on the ruins of the villa on the south-western end of the (in those times still usable) roman bridge, to the Bishopric of Metz. Between 601 and 609, Bishop Arnual founded a community of clerics, a Stift, there. Centuries later the Stift, and in 1046 Merkingen, took on his name, giving birth to St Arnual.
The oldest documentary reference to Saarbr�cken is a deed of donation from 999, which documents that Emperor Otto III gave the "castellum Sarabrucca" (Saarbr�cken castle) to the Bishops of Metz. The Bishops gave the area to the Counts of Saargau as a fief. By 1120, the county of Saarbr�cken had been formed and a small settlement around the castle developed. In 1168, Emperor Barbarossa ordered the slighting of Saarbr�cken because of a feud with Count Simon I. The damage cannot have been grave, as
