During the reign of Augustus from 27 BCE until 14 CE, the Roman empire became established in Gaul, with the Rhine as a border. From 12 to 9 BCE, the Roman Empire dominated the region between the Rhine and the Weser, and possibly also the region between the Weser and Elbe, apparently aiming to create a new Roman province in "Germania". Following the Roman defeat at the Battle of the Teutoburg Forest in 9 CE, Rome gave up on the possibility of fully integrating this region into their empire. In the reign of his successor Tiberius it became state policy to expand the empire no further than the frontier based roughly upon the Rhine and Danube. The Julio-Claudian dynasty, the extended family of Augustus, paid close personal attention to management of this Germanic frontier, establishing a tradition followed by many future emperors. Major campaigns were led from the Rhine personally by Nero Claudius Drusus, step-son of Augustus, then by his brother the future emperor Tiberius; next by the son of Drusus, Germanicus (father of the future emperor Caligula and grandfather of Nero).