Arbayistan

Arbāyistān (Parthian: 𐭀𐭓𐭁𐭉𐭎𐭈𐭍 [ʾrb]ystn; Middle Persian: Arbāyistān, Arāwastān, Arwāstān; Armenian: Arvastan) or Beth Arabaye (Syriac: Bēṯ ʿArbāyē) was a Sasanian province in Late Antiquity. Due to its situation and its road systems, the province was a source of income from commercial traffic, as well as a constant area of contention during the Roman–Persian Wars.

The province reached across Upper Mesopotamia toward the Khabur and north to the lower districts of Armenia; it bordered Adiabene in the east, Armenia in the north and Asoristan in the south. On the west, it bordered the Roman provinces of Osroene and Mesopotamia. The principal city of the Arbayistan province was Nisibis and it also included the fortress of Sisauranon.

Arbāyistān (from Old Persian Arabāya-stāna) is mentioned in Shapur I's inscription at the Ka'ba-ye Zartosht. The terms Arbāyistān and Syriac Beth ʿArbaye literally mean "land of the Arabs", using the suffix -istān ("land") and the word beth ("house"), respectively. The Romans called it Arabia. According to historian Geo Widengren, the name refers to the Arab inhabitants of Upper Mesopotamia.

Arbayistan is first attested as a province in the Ka'ba-ye Zartosht inscription of the second Sasanian King of Kings (shahanshah) Shapur I (r. 240–270), which was erected in c. 262. The province was lost after Peace of Nisibis (299), when Narseh ceded northern Mesopotamia to the Romans. This included the former Armenian provinces of Corduene, Zabdicene, Arzanene and Moxoene as well as Nisibis and Singara. It was restored in 363 after the 2nd Peace of Nisibis, composed of the concessions made by Roman Emperor Jovian, which encompassed all Roman territory east of the Tigris that had been ceded by the Sasanians in the 1st Peace of Nisibis in 299. As part of the treaty, the Romans were allowed to evacuate the inhabitants of the cities of Nisibis and Singara, and this led to the mass exodus of the entire populations of both cities to Roman territories to avoid imprisonment and deportation by the Sasanians. This also caused the Christian School of Nisibis to move to Edessa. In the 360s, Shapur II divided the office of marzban between his brothers Zamasp and Adurfrazgird and they were granted responsibility for the northern and southern halves of the province respectively.

As a result of the Peace of Acilisene of 387, Armenia was divided between the Eastern Roman and Sasanian Empires and the majority of Arzanene was given to the Romans, aside from the canton of Arzan itself. In the fourth century, 12,000 Persians from Istakhr, Spahan and other regions were settled in Nisibis to act as mainly military garrisons. At the close of the fourth century, in 395, the Huns breached the Caspian Gates and swarmed through the east, plundering Armenia and Eastern Roman Cappadocia, Cilicia and Syria undisturbed until moving to raid Sasanian Arbayistan in 398.

During the Roman–Sasanian War of 421–422, the magister militum per Orientem, Ardaburius, invaded and plundered Arzanene in 421. Ardaburius engaged and defeated the Sasanian grand vizier, Mihr Narseh, and with reinforcements besieged Nisibis. The army of Al-Mundhir I, an ally of the Sasanians, who had been sent to relieve Nisibis, was defeated by Ardaburius beneath the walls and dispersed. Ardaburius' victory over Al-Mundhir I led the new Shah, Bahram V, to end his siege of Theodosiopolis and march to relieve Nisibis, causing the Romans to abandon the siege.

From 464 to 471, a famine struck Mesopotamia which devastated the crops and ruined the country. Sources say that the wells became dry and that there was not a trickle of water either in the Tigris or the Euphrates. Eventually the crops failed and thousands perished. In 483, a severe drought affected the region and lasted for two years, during which time tensions between the Romans and Persians heightened as Arab nomads allied to the Persians raided Roman territory, causing the Romans to assemble an army on the frontier to counter such raids. The situation was defused, however, by the marzban of Nisibis and Nestorian metropolitan bishop of Nisibis, Barsauma. Three years into the reign of Kavad I (r. 488–496, 498/9–531), in 491, an uprising in Armenia encouraged the Qadishaye tribesmen south of Singara to revolt and besiege Nisibis.

At the time of the Anastasian War, Kavad I besieged and sacked the city of Amida in 503, and resettled the population in Singara. The loss of Amida spurred the Roman emperor Anastasius I Dicorus to send reinforcements to the Persian border, however, a Roman army that crossed over into Arzanene was defeated. In the spring of 504, the Roman general Celer invaded Arbayistan and conducted raids against fortified settlements, seizing several forts and plundering the province, killing farmers and livestock alike.