It was erected in the last decade of the 1st century BC and was dedicated to the goddess Roma and the Roman emperor.
It was a central location for the Germans conquered by Augustus to demonstrate their loyalty to Rome and the Emperor through offerings.
Like the Ara trium Galliarum, the altar was the site of the concilium provinciae ("pronvicial council") for the planned province of Germania Magna.
When he learnt of the defeat of Publius Quinctilius Varus in the Battle of the Teutoburg Forest, Segimundus is meant to have ripped the priestly headband from his head and fled over the Rhine to Germany in order to join the war effort.
The Oppidum Ubiorum was located within the walls erected after the founding of the colonia, probably on the main street of the Roman city, which ran through the forum.