Valentinian II (; 37115 May 392) was a Roman emperor in the western part of the Roman empire between AD 375 and 392. He was at first junior co-ruler of his brother, was then sidelined by a usurper, and only after 388 sole ruler, albeit with limited de facto powers. A son of emperor Valentinian I and empress Justina, he was raised to the imperial office at the age of 4 by military commanders upon his father's death. Until 383, Valentinian II remained a junior partner to his older half-brother Gratian in ruling the Western empire, while the East was governed by his uncle Valens until 378 and Theodosius I from 379. When Gratian was killed by the usurper emperor Magnus Maximus in 383, the court of Valentinian in Milan became the center of Italy where several religious debates took place. In 387, Maximus invaded Italy, spurring Valentinian and his family to escape to Thessalonica where they successfully sought Theodosius' aid. Theodosius defeated Maximus in battle and re-installed Valentinian in the West. However, Valentinian soon found himself struggling to break free from the control of general Arbogast. In 392, Valentinian was discovered hanged in his room under unknown circumstances. Early life and accession (371–375) Valentinianus was born to Emperor Valentinian I and his second wife, Justina. He was the half-brother of Valentinian's other son, Gratian, who had shared the imperial title with his father since 367. He had three sisters: Galla, Grata and Justa. The elder Valentinian died on campaign in Pannonia in 375. Neither Gratian (then in Trier) nor his uncle Valens (emperor for the East) were consulted by the army commanders on the scene. Instead of merely acknowledging Gratian as his father's successor, Valentinian I's leading generals and officials, including Merobaudes, Petronius Probus, and Cerealis, Valentinian II's maternal uncle and Justina's brother, acclaimed the four-year-old Valentinian augustus on 22 November 375 at Aquincum. The army, and its Frankish general Merobaudes, may have been uneasy about Gratian's lack of military ability, and to prevent a split of the army, so raised a boy who would not immediately aspire to military command. Also, he may have wanted to prevent more successful military commanders and officials, such as Sebastianus and Count Theodosius, from becoming emperors or gaining independent power, as Sebastianus was removed to a distant posting and Theodosius was executed within a year of Valentinian's elevation. Reign from Milan (375–387)