Another faction, led by two other dissatisfied nobles, Vistahm and Vinduyih, had Hormizd IV deposed and killed, and elevated his son Khosrow II as the new king (shah).

Modern historiography presents a milder view of him, and considers him a well-meaning ruler who strived to continue his father's policies, albeit overambitiously.

Hormizd (also spelled Ōhrmazd and Hormozd) is the Middle Persian version of the name of the supreme deity in Zoroastrianism, known in Avestan as Ahura Mazda.

[6] This is, however, rejected by the Iranologist Shapur Shahbazi, who called such a relationship a "chronological difficulty", due to sources mentioning Hormizd being sent by his father to contain the threat posed by Istemi, following the division of Hephthalite territory between the Sasanians and Turks.

[6] The decision was also politically motivated, due to Hormizd's maternal line being of noble lineage, whilst the mothers of Khosrow I's other sons were more lowly.

[9] He appears to have strived his best to continue the policies of his father—supporting the landed gentry (the dehqan) against the aristocracy and protecting the rights of the lower classes, as well as thwarting efforts by the Zoroastrian priesthood to reassert themselves.

[13] Hormizd was not the first Sasanian shah to kill a close relative from the Ispahbudhan family: his father Khosrow I had ordered the execution of Bawi in the early 530s.

[14] Nevertheless, the Ispahbudhans continued to enjoy such a high status that they were acknowledged as "kin and partners of the Sasanians", with Vistahm being appointed as the successor of his father by Hormizd.

[6][15] This was not unusual: the 5th-century Sasanian ruler Yazdegerd I is portrayed very negatively in Persian sources due to his tolerant policy towards his non-Zoroastrian subjects, and his refusal to comply with the demands of the aristocracy and priesthood, thus becoming known as the "sinner".

The German orientalist Theodor Nöldeke deemed the negative portrayal of Hormizd as unreasonable, and considered the shah to be "a well-meaning sovereign who intended to restrain the nobility and clergy and ease the burden of the lower classes: his effort was on the whole justified, but the unhappy outcome shows that he was not the man to reach such lofty goals with peace and competence".

[6] The modern historian Michael Bonner states that "the Persian royal tradition has covered Hurmazd in opprobrium, and the principal features of his reign have been deformed.

Negotiations of peace had just begun with the Emperor Tiberius II, who offered to give up all claims to Armenia and interchange the Byzantine-occupied Arzanene for the Iranian-occupied Dara (which was an important Byzantine stronghold).

[20] The Byzantines were successful at their endeavors, securing a noteworthy victory under the commanders Cours and John Mystacon, albeit also suffering a defeat at the hands of the Sasanians.

He appointed his son Khosrow as the governor of Caucasian Albania, who negotiated with the Iberian aristocracy and won their support, so successfully incorporating the country into the Sasanian Empire.

[21][7][22] The following year (581), an ambitious campaign by the Byzantine commander Maurice, supported by Ghassanid forces under al-Mundhir III, targeted the Sasanian capital of Ctesiphon.

[23][24] In response to Maurice's advance, the Iranian general Adarmahan was ordered to operate in northern Mesopotamia, threatening the Byzantine army's supply line.

[6] Meanwhile, John Mystacon, who had replaced Maurice as the Commander of the East, attacked the Sasanians at the junction of the Nymphius and the Tigris, but was defeated by the Iranian general Kardarigan.

The siege failed, and he then marched north to Martyropolis, Philippicus's base; after sacking the church of John the Baptist near the city, however, he returned to Iranian territory, most likely Armenia.

[37][40] He managed to reach as far as Baykand, near Bukhara, and also contain an attack by the son of the deceased Khagan, Birmudha, whom Bahram had captured and sent to Ctesiphon.

[39][a] This victory briefly made Iran the supreme power in Near East, a feat that was for a long time evoked in Persian stories.

[37] Due to his noble status and great military knowledge, Bahram's soldiers and many others joined the rebellion,[37] which marked the start of the Sasanian civil war of 589–591.

[37] The legitimacy of the House of Sasan had been established in the credence that the halo of kingship, the xwarrah, was given to the first Sasanian shah, Ardashir I (r. 224–242) and his family following the latter's conquest of the Parthian Empire (also known as the Arsacids).

[37] A verse in the Shahnameh seemingly indicates that Bahram proclaimed himself as the personification of the fire of the sun god Mithra, and that he swore to restore the religion and traditions of his ancestors, the Arsacids.

[47] The route taken by Bahram was presumably the northern edge of the Iranian plateau, where in 590 he had repelled a Byzantine-funded attack by Iberians and others on Adurbadagan, and suffered a minor setback by a Byzantine force employed in Transcaucasia.

[7][49] He then sent an envoy to placate Bahram, while he started to make preparations to collect the royal treasure, destroy the bridge of the Tigris, and take sanctuary in al-Hira, the capital of the Lakhmids.

[7][11] They had Hormizd blinded with a red-hot needle, and put his oldest son Khosrow II (who was their nephew through his mother's side) on the throne.

[39] Hormizd's death continued to be a controversial matter—a few years later, Khosrow II ordered the execution of both his uncles as well as other nobles who had a hand in the killing of his father.

[56] Since the 5th-century, the Sasanian monarchs had been made aware of the significance of the religious minorities in the realm, and as a result tried to homogenize them into a structure of administration where according to legal principles, all would be treated straightforwardly as mard / zan ī šahr, i.e. "man/woman citizen (of the Empire)".

[58] According to al-Tabari's History of Prophets and Kings and the Chronicle of Seert, which both drew some of their work from the Middle Persian history book Khwaday-Namag ("Book of Lords"), Hormizd told the clergy:[59] "Just as our royal throne cannot stand on its two front legs without the two back ones, our kingdom cannot stand or endure firmly if we cause the Christians and adherents of other faiths, who differ in belief from ourselves, to become hostile to us.

[60] Hormizd was himself married to a Christian woman and prayed to the martyr St. Sergius, a military saint whose cult rapidly increased beyond political and cultural borders from the 5th to the 7th-century.