Sophia participated in the governance of the empire; she took an interest in the financial and foreign policies, and served as regent alongside Tiberius II during Justin's incapacity from 573 until 578.

According to John of Ephesus and Michael the Syrian, Sophia and Justin were both initially Monophysites who converted to Chalcedonianism to gain favor with their uncle Justinian.

He managed to gain the support of the Senate and was proclaimed emperor within the palace walls before the other members of the Justinian Dynasty were notified.

The accession speech of Justin makes specific mention of Sophia co-ruling with her husband, the presumption being that she already exercised political influence.

Corippus also includes an elaborate account of the Hagia Sophia, mainly as a compliment to the empress who shared its name.

[8] Corippus also records Sophia being in charge of the arrangements for the funeral of Justinian and claims she wove his shroud with scenes depicting the triumphs of his reign.

She was the first empress consort depicted on Byzantine coinage with royal insignia equal to her husband, and this coin type continued up to Phocas and Leontia.

According to Evagrius Scholasticus, the Emperor and Sophia initially welcomed their kinsman to Constantinople but before long had him exiled to Alexandria.

According to Paul the Deacon, Sophia sent a message to the senior general that she had a more suitable position for a eunuch like him, as an overseer of the weaving girls of the gynaikonitis (women's quarters).

Narses chose to retire to Naples, instead of returning to Constantinople as Justin had ordered him to do and invited the Lombards to invade.

Evagrius, John of Ephesus, Gregory of Tours, and Paul the Deacon all mention this while accusing both Justin and Sophia of greed.

John of Ephesus writes that in her rage Sophia claimed that Tiberius had "reduced the state to poverty" and that it took her years to accumulate he was "spending in no time at all", which may show her ongoing importance in financial policy after the death of Justin.

They also sent relics to Pope John III in an attempt to improve relations: the Cross of Justin II in the Vatican Museums, a crux gemmata, and a reliquary of the True Cross perhaps given at this point, has an inscription recording their donation and apparently their portraits on the ends of the arms on the reverse.

Justin reportedly suffered from temporary fits of insanity and was unable to perform his duties as early as the fall of Dara to Khosrau I of the Sassanid Empire in November, 573.

However, East Roman historians such as Evagrius Scholasticus and Menander Protector state that Tiberius, who was the commander of the Excubitors (comes excubitorum), gained power alongside Sophia.

[18] Both the Ecclesiastical History of John of Ephesus and the Chronicle of Theophanes the Confessor suggest that Sophia was planning to marry Tiberius at this point.

[1] Theophanes, writing centuries later, suggests Sophia did not know Tiberius was already married during this period, but this claim is contradicted by John of Ephesus, a 6th-century writer.

According to John of Ephesus, Sophia sent Patriarch Eutychius of Constantinople to Tiberius to convince him to divorce Ino, and offered both herself and her adult daughter Arabia as prospective brides.

Gregory of Tours records that Sophia took part in a conspiracy to depose Tiberius and replace him with another Justinian, younger brother of the Justin murdered in Alexandria.

Gregory of Tours reported that Sophia had planned to marry Tiberius to regain the throne, but the marriage of Constantina and Maurice took place in Autumn 582.

John of Ephesus mentions that all three augustas resided in the Great Palace,[1] which would mean either that Sophia's retirement was temporary or that Theophanes misreported her status.