To the east, in an alliance with the Göktürks, he finally put an end to the Hephthalite Empire, which had inflicted a handful of defeats on the Sasanians in the 5th century, killing Khosrow's grandfather Peroz I.

During his ambitious reign, he continued his father's project of making major social, military, and economic reforms, promoting the welfare of the people, increasing state revenues, establishing a professional army, and founding or rebuilding many cities, palaces, and much infrastructure.

[2] Syriac authors, such as John of Ephesus and Zacharias Rhetor also include Khosrow in their work, offering a perception of the consequences that his expeditions brought on the people who lived on the Roman border.

[8][9] The town, dating back to the Achaemenid period, thrived during Khosrow's age, and also included a fire temple, which was said to be founded by the mythological Kayanian king Kay Bahman,[8] from whom the Sasanians claimed their descent.

[15] In c. 520, Kavad, in order to secure the succession of Khosrow, whose position was threatened by rival brothers and the Mazdakite sect, proposed that Emperor Justin I adopt him.

[21][22] According to modern historians Touraj Daryaee and Matthew Canepa, sharing women was most likely an overstatement and defamation deriving from Mazdak's decree that loosened marriage rules to help the lower classes.

[26] Khosrow succeeded him, but due to his domestic position being insecure, he wanted to make peace with the Byzantines, who themselves under Emperor Justinian I (r. 527–565) were perhaps already more focused on recovering the lost western half of the Roman Empire than in pursuing war against Iran.

Justinian would pay 110 centenaria (11,000 pounds) of gold, ostensibly as a contribution to the defence of the Caucasus passes against the barbarians living beyond, and the base of the dux Mesopotamiae would be withdrawn from the fortress of Dara to the city of Constantina.

[29] In summer 532, however, a new embassy by Hermogenes and Rufinus managed to persuade Khosrow for a full exchange of the occupied forts, as well as for allowing the exiled Iberian rebels to either remain in the Byzantine Empire or return safely to their homes.

The subsequent reforms resulted in the rise of a bureaucratic state at the expense of the great noble families, strengthening the central government and the power of the Shahanshah.

[37] Prior to Khosrow and Kavad's reigns, a majority of the land was owned by seven Parthian families: Suren, Waraz, Karen, Ispahbudhan, Spandiyadh, Mihran and Zik.

[46] Subsequently, Khosrow accused Justinian of trying to bribe the Lakhmid ruler al-Mundhir III ibn al-Nu'man (r. 503–554) through his diplomat Summus, and also that he had emboldened some Huns to make incursions into Iran.

[51] Khosrow extracted tribute from Apamea and other Byzantine towns, at which point Justinian called off his truce and prepared to send his commander Belisarius to move against the Sasanians.

The last major decisive battle of the Lazic wars came in 556 when Byzantine general Martin defeated a massive Sasanian force led by an Iranian nakhvaegan (field marshal).

[54] Negotiations between Khosrow and Justinian opened in 556, leading to the Fifty-Year Peace Treaty in 562 in which Iranians would leave Lazica in return for an annual payment of gold.

It is agreed that Saracen and all other barbarian merchants of either state shall not travel by strange roads but shall go by Nisibis and Daras, and shall not cross into foreign territory without official permission.

But if they dare anything contrary to the agreement (that is to say, if they engage in tax-dodging, so-called), they shall be hunted down by the officers of the frontier and handed over for punishment together with the merchandise which they are carrying, whether Assyrian or Roman.

A large force, beyond what is adequate to defend the town, shall not be stationed at Daras, and the general of the East shall not have his headquarters there, in order that this not lead to incursions against or injury to the Persians.

[57] Even with the growth of Iranian military power under Khosrow's reforms, the Sasanians were still uneasy at the prospect of attacking the Hephthalite on their own and began to seek allies.

The alliance contained a treaty that made it obligatory for Faghanish to be sent to the Sasanian court in Ctesiphon and gain the approval of Khosrow for his status as Hephthalite king.

After being denied by Justinian, Ma'd-Karib sought help from Khosrow, who sent a small fleet and army under commander Vahrez to depose the current king of Yemen.

In 555, the Sasanian governor of Armenia and a relative of Khosrow, Chihor-Vishnasp (also known as Suren), built a fire temple at the Armenian capital Dvin and put to death a popular and influential member of the Mamikonian family.

During the same time, the Siunian prince Vahan asked for Khosrow's permission that he could move his court from Dvin to the capital of Paytakaran, a region in eastern Armenia.

[75] During the same time, one of Khosrow's chief generals, Tamkhosrau, managed to trick Maurice by faking an invasion of Theodosiopolis, and then plundered the countryside of Martyropolis and Amida.

[78] 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).

[85] This was due to the royal anxieties regarding the chance of religious rogues to upset the political structure, which had recently occurred during Kavad and Khosrow's reigns by the Mazdakites.

[35] According to Middle Persian sources, Khosrow I ordered the construction of the Great Wall of Gorgan, which extended from the eastern coast of the Caspian Sea to block incursions by nomadic tribes, such as the Hephthalites.

An entry in the Chronicle of Séert reads: Khosrau was very learned in philosophy, which he had studied, it is said, under Mar Bar Samma, the Syriac bishop of Qardu, and under Paul the Persian.

[102] According to some historical accounts, this famous learning center was built in order to provide a place for incoming Greek refugees to study and share their knowledge.

[99] Richard Frye argues that Khosrow's rationale behind his numerous wars with the Byzantine empire as well as the eastern Hephthalites was to establish the Sasanian dominance on this trade route.