Surena was a member of the House of Suren, one of the Seven Great Houses of Iran. The family, of Parthian origin, had been active in Iranian politics since the Arsacid Empire, and held parts of Sakastan as their personal fiefdom. Surena was seemingly a powerful figure in the country, being described as "second in power after the king." He is first mentioned in 363, when he on April 24 ambushed a patrol force led by Hormizd, a brother of Shapur II, who had entered the service of the Roman emperor Julian ().Marcellinus, xxiv. Hormizd only managed to escape due to the overflow of the Euphrates which proved too much for Surena and his men. The following day after the Roman sack of Pirisabora, Surena ambushed three squadrons of the Roman cavalry, killing some of them, including one of the tribunes, and also captured an aquila.
