Parthian was an Iranian language written in the Aramaic alphabet. It had an enormous number of words and even phrases that were borrowed from Aramaic, and scribal training was necessary to learn these. Syriac, being a Semitic language with emphasis on consonants, evolved several alphabets based on the Aramaic alphabet. The Aramaic alphabet was better suited to Syriac than to Parthian phonology. Parthian was therefore difficult to read and was mainly used by scribes or priests for official or religious writings.
The largest lacuna is in literature from the Parthian period. The largely oral literature of the Parthians, famous for their minstrels and poetry, does not seem to have found many echoes in Mesopotamia, where the settled society contrasted with the heroic, chivalric, and feudal society of the Iranian nomads that continued to dominate Parthian mores even after they had settled in Mesopotamia. Nonetheless, the end of the Parthian period saw the beginning of Syriac literature, which is Christian Aramaic, and some of early Syriac literature, such as the “Song of the Pearl,” contains Parthian elements. In the realm of language, rather than literature, the writing of Aramaic changes to Parthian in the 2nd century ce, as can be seen from a bilingual (Greek and Parthian) inscription on a bronze statue from Seleucia dated 150–151 ce. It tells how Vologeses III defeated the king of Mesene and took over the entire country. After this period one no longer speaks of Aramaic, but of Parthian and Syriac written in a new cursive alphabet.
The Sāsānian period
The Sāsānian period marks the end of the ancient and the beginning of the medieval era in the history of the Middle East. Universalist religions such as Christianity, Manichaeism, and even Zoroastrianism and Judaism absorbed local religions and cults at the beginning of the 3rd century. Both the Sāsānian and the Roman empires ended by adopting an official state religion, Zoroastrianism for the former and Christianity for the latter. In Mesopotamia, however, older cults such as that of the Mandaeans, the moon cult of Harran, and others continued alongside the great religions. The new rulers were not as tolerant as the Seleucids and Parthians had been, and persecutions occurred under Sāsānian rule.
After Ardashīr I, the first of the Sāsānians, consolidated his position in Persis (modern Fārs province), he moved into southern Mesopotamia, and Mesene submitted. In 224 he defeated and killed the last Parthian ruler, Artabanus V, after which Mesopotamia quickly fell before him and Ctesiphon became the main capital of the Sāsānian empire. In 230 Ardashīr besieged Hatra but failed to take it. Hatra called on Roman aid, and in 232 the Roman emperor Severus Alexander launched a campaign that halted Ardashīr’s progress. At the death of Severus Alexander in 235 the Sāsānians took the offensive, and probably in 238 Nisibis and Harran came under their control. Hatra was probably captured in early 240, after which Ardashīr’s son Shāpūr was made coregent; Ardashīr himself died soon afterward. The Roman emperor Gordian III led a large army against Shāpūr I in 243. The Romans retook Harran and Nisibis and defeated the Sāsānians at a battle near Resaina, but at Anbār, renamed Pērōz-Shāpūr (“Victorious Is Shāpūr”), the Sāsānians inflicted a defeat on the Romans, who lost their emperor. His successor, Philip the Arabian, made peace, giving up Roman conquests in northern Mesopotamia. Osroene, however, which had been returned to the local ruling family of Abgar by Gordian, remained a vassal state of the Romans. Shāpūr renewed his attacks and took many towns, including Dura-Europus, in 256 and later moved into northern Syria and Anatolia. The defeat and capture of the Roman emperor Valerian at the gates of Edessa, probably in 259, was the high point of his conquests in the west. On Shāpūr’s return to Ctesiphon the ruler of Palmyra, Septimius Odaenathus (also called Odainath), attacked and defeated his army, seizing booty. Odeanathus took the title of emperor, conquered Harran and Nisibis, and threatened Ctesiphon in 264–266. His murder relieved the Sāsānians, and in 273 the Roman emperor Aurelian sacked Palmyra and restored Roman authority in northern Mesopotamia. Peace between the two empires lasted until 283, when the Roman emperor Carus invaded Mesopotamia and advanced on Ctesiphon, but the Roman army was forced to withdraw after Carus’ sudden death. In 296 Narseh I, the seventh Sāsānian king, took the field and defeated a Roman force near Harran, but in the following year he was defeated and his family was taken captive. As a result, the Romans secured Nisibis and made it their strongest fortress against the Sāsānians. The Roman province of Mesopotamia, which was the land between the Euphrates and Tigris in the northern foothills, became in effect a military area with limes (the fortified frontiers of the Roman Empire) and highly fortified towns.
Under Shāpūr II the Sāsānians again took the offensive, and the first war lasted from 337 to 350; it ended with no result as Nisibis was successfully defended by the Romans. In 359 Shāpūr again invaded Roman territory and captured the Roman fortress Amida after a long and costly siege. In 363 the emperor Julian advanced almost to Ctesiphon, where he died, and his successor Jovian had to give up Nisibis and other territories in the north to the Sāsānians. The next war lasted from 502 to 506 and ended with no change. War broke out again in 527, lasting until 531, and even the Byzantine general Belisarius was not able to prevail; as usual, the boundaries remained unchanged. In 540 the Sāsānian king Khosrow (Chosroes) I invaded Syria and even took Antioch, although many fortresses behind him in northern Mesopotamia remained in Byzantine hands. After much back-and-forth fighting, peace was made in 562. War with the Byzantine Empire resumed 10 years later, and it continued under Khosrow’s successor, Hormizd IV. Only in 591, in return for their assistance in the restoration to the Sāsānian throne of Khosrow II, who had been deposed and had fled to Byzantine territory, did the Byzantines regain territory in northern Mesopotamia. With the murder in 602 of the Byzantine emperor Maurice, who had been Khosrow’s benefactor, and the usurpation of Phocas, Khosrow II saw a golden opportunity to enlarge Sāsānian domains and to take revenge for Maurice. Persian armies took all northern Mesopotamia, Syria, Palestine, Egypt, and Anatolia. By 615, Sāsānian forces were in Chalcedon, opposite Constantinople. The situation changed completely with the new Byzantine emperor Heraclius, who, in a daring expedition into the heart of enemy territory in 623–624, defeated the Sāsānians in Media. In 627–628 he advanced toward Ctesiphon, but, after sacking the royal palaces at Dastagird, northeast of Ctesiphon, he retreated.
After the death of Khosrow II, Mesopotamia was devastated not only by the fighting but also by the flooding of the Tigris and Euphrates, by a widespread plague, and by the swift succession of Sāsānian rulers, which caused chaos. Finally in 632 order was restored by the last king, Yazdegerd III, but in the following year the expansion of the Muslim Arabs began and the end of the Sāsānian empire followed a few years afterward.