eastward, Tiberius sent his general Justinian with the eastern armies to push the Persians back across the Euphrates. The Byzantines followed, and pushed deep into Persian territory, culminating in a raid on Atropatene. In 577, however, Justinian was defeated in Persian Armenia, forcing a Byzantine withdrawal. In response to that defeat, Tiberius replaced Justinian with the future emperor Maurice. During the truce that Tiberius concluded with Khosrau, he busily enhanced the army of the east not only with transfers from his western armies but also through barbarian recruits, which he formed into a new foederati unit, amounting to some 15,000 troops by the end of his reign. Throughout 577 and into 578, Tiberius avoided all other entanglements that would have distracted him from the approaching Persian conflict. He appeased, quite successfully, both Chalcedonian and Monophysite Christians by the use of strategic appointments and the easing of persecutions. He paid the Lombard tribal chieftains some 200,000 nomismata in an attempt to keep them divided and to prevent the election of a king. When the Slavs invaded Illyricum, he transported Avar armies to attack them and force their retreat. Consequently, when Khosrau invaded Roman Mesopotamia in 578, his general, Maurice, was able to invade Persian Arzanene and Mesopotamia, sacking a number of key towns and forcing the Persians to abandon their advance and defend their own territory. It was during that period that the ailing emperor, Justin, finally died on 5 October 578. Reign as augustus (578–582) On 26 September 578, Tiberius was made Augustus by the rapidly-failing Justin. He used that opportunity to give away 7,200 pounds of gold, a practice that he continued annually throughout the four years of his reign. Sophia, Justin's widow, tried to maintain her power and influence by marrying the new emperor, but he refused her proposal because he was already married to Ino. When Tiberius had first been raised to the rank of Caesar, Sophia had refused the request for Ino and her children to move into the Imperial palace with her husband, forcing them to reside in a small residence nearby and prohibiting them from entering the palace. Once Tiberius was elevated to the rank of Augustus, however, he had his family moved into the palace and renamed Ino as Anastasia, much to Sophia's resentment. Therefore, Sophia sought revenge, and a secret pact was made between the dowager empress and General Justinian, whom Tiberius