The history of the city goes back to the Roman Empire. The Romans started a military camp called Vindobona. The camp was in today's first district on the Danube river. The name came from the Celts, so there was probably a Celtic settlement before the Roman invasion. The Romans stayed until the 5th century. In medieval times, the settlement was still in use. The present name was mentioned in 881 in the Salzburger Annalen, where a battle "ad weniam" is mentioned.