domestici under the emperors Julian () and Jovian (). According to the 5th-century Greek historian Socrates Scholasticus, Valens refused pressure to offer pagan sacrifices during the reign of the polytheist emperor Julian. Valens's elder brother Valentinian also joined the protectores, rising to tribunus in 357; he served in Gaul and in Mesopotamia during the reign of Constantius II (). According to the Chronicle of Jerome and the Chronicon Paschale, Valens's eldest nephew Gratian was born in 359 at Sirmium (Sremska Mitrovica) to Valentinian's wife Marina Severa. Julian was killed in battle against the Persians in June 363, and his successor Jovian hastened towards Constantinople to secure his claim to the purple. Before reaching the capital, Jovian died unexpectedly at Dadastana in February 364. During his brief reign, he had given Valentinian the rank of tribunus scholae secundiae scutariorum. The Latin historian Ammianus Marcellinus relates that Valentinian was summoned to Nicaea by a council of military and civil officials, who acclaimed him augustus. According to the Consularia Constantinopolitana and the Chronicon Paschale, the date of his elevation was 25 February 364. Accession Valentinian appointed his brother Valens tribunus stabulorum (or stabuli) on 1 March 364 and both brothers became Roman consul for the first time. It was the general opinion that Valentinian needed help to handle the administration, civil and military, of the large and unwieldy empire, and, on 28 March of the same year, at the express demand of the soldiers for a second augustus, he selected his brother Valens as co-emperor at the Hebdomon, before the Constantinian Walls. Early reign Both emperors were briefly ill, delaying them in Constantinople. As soon as they recovered, the two augusti travelled together through Adrianople and Naissus to Mediana, where they divided their territories. Valens obtained the eastern half of the Empire: Greece, the Balkans, Egypt, Anatolia and the Levant as far as the border with the Sasanian Empire. Valentinian took the western half, where the Alemannic wars required his immediate attention. The brothers began their consulships in their respective capitals, Constantinople and Mediolanum (Milan). Valens's wife Domnica may have become augusta in 364. In the summer of 365, the 365 Crete earthquake and ensuing tsunami caused destruction around the Eastern Mediterranean. The empire had recently retreated from most of its holdings in Mesopotamia and Armenia, because of a treaty that Jovian had made with Shapur II of the Sasanian Empire. Valens's first