BC) (at the Battle of Carrhae), Decidius Saxa (40 BC), and Mark Antony (36 BC). After a year of negotiation, Tiberius led a sizable force into Armenia, presumably to establish it as a Roman client state and end the threat it posed on the Roman-Parthian border. Augustus was able to reach a compromise whereby the standards were returned, and Armenia remained a neutral territory between the two powers. Tiberius married Vipsania Agrippina, the daughter of Augustus' close friend and most famed general, Marcus Vipsanius Agrippa. He was appointed to the position of praetor, and was sent with his legions to assist his brother Drusus in campaigns in the west. While Drusus focused his forces in Gallia Narbonensis and along the German frontier, Tiberius combated the tribes in the Alps and within Transalpine Gaul, conquering Raetia. In 15 BC he discovered the sources of the Danube, and soon afterward the bend of the middle course. Returning to Rome in 13 BC, Tiberius was appointed as consul, and around this same time his son, Drusus Julius Caesar, was born. Agrippa's death in 12 BC elevated Tiberius and Drusus with respect to the succession. At Augustus' request in 11 BC, Tiberius divorced Vipsania and married Julia the Elder, Augustus' daughter and Agrippa's widow. Tiberius was very reluctant to do this, as Julia had made advances to him when she was married, and Tiberius was happily married. His new marriage with Julia was happy at first, but turned sour. Suetonius claims that when Tiberius ran into Vipsania again, he followed her home crying and begging forgiveness; soon afterwards, Tiberius met with Augustus, and steps were taken to ensure that Tiberius and Vipsania would never meet again. Tiberius continued to be elevated by Augustus, and after Agrippa's death and his brother Drusus' death in 9 BC, seemed the clear candidate for succession. As such, in 12 BC he received military commissions in Pannonia and Germania, both areas highly volatile and of key importance to Augustan policy. Military campaigns In 6 BC, Tiberius launched a pincer movement against the Marcomanni. Setting out northwest from Carnuntum on the Danube with four legions, Tiberius passed through Quadi territory in order to invade Marcomanni territory from the east. Meanwhile, general Gaius Sentius Saturninus would depart east from Moguntiacum on the Rhine with two or three legions, pass through newly annexed Hermunduri territory, and attack the Marcomanni from the west.