Mithridates I of Parthia in the context of "Hyrcania"

The Parthian Empire (/ˈpɑːrθiən/), also known as the Arsacid Empire (/ˈɑːrsəsɪd/), was a major Iranian political and cultural power centered in ancient Iran from 247 BC to 224 AD. Its latter name comes from its founder, Arsaces I, who led the Parni tribe in conquering the region of Parthia in Iran's northeast, then a satrapy (province) under Andragoras, who was rebelling against the Seleucid Empire. Mithridates I (r. c. 171 – 132 BC) greatly expanded the empire by seizing Media and Mesopotamia from the Seleucids. At its height, the Parthian Empire stretched from the northern reaches of the Euphrates, in what is now central-eastern Turkey, to present-day Afghanistan and western Pakistan. The empire, located on the Silk Road trade route between the Roman Empire in the Mediterranean Basin and the Han dynasty of China, became a center of trade and commerce.

The Parthians largely adopted the art, architecture, religious beliefs, and regalia of their culturally heterogeneous empire, which encompassed Persian, Hellenistic, and regional cultures. For about the first half of its existence, the Arsacid court adopted elements of Greek culture, though it eventually saw a gradual revival of Iranian traditions. The Arsacid rulers were titled "King of Kings", claiming inheritance of the Achaemenid Empire; indeed, they accepted many local kings as vassals, although the Achaemenids would have had centrally appointed, albeit largely autonomous, satraps. The court did appoint a small number of satraps, largely outside Iran, but these satrapies were smaller and less powerful than the Achaemenid potentates. With the expansion of Arsacid power, the seat of central government shifted from Nisa to Ctesiphon along the Tigris (south of Baghdad), although several other sites also served as capitals.

Arsaces I (/ˈɑːrsəsiːz/; from Ancient Greek: Ἀρσάκης; in Parthian: 𐭀𐭓𐭔𐭊‎, romanized: Aršak) was the first king of Parthia, ruling from 247 BC to 217 BC, as well as the founder and eponym of the Arsacid dynasty of Parthia. The leader of the Parni, one of the three tribes of the Dahae confederacy, Arsaces founded his dynasty in the mid-3rd century BC when he conquered the satrapy of Parthia (now shared between Turkmenistan and Iran) from Andragoras, who had rebelled against the Seleucid Empire. He spent the rest of his reign consolidating his rule in the region, and successfully stopped the Seleucid efforts to reconquer Parthia. Due to Arsaces' achievements, he became a popular figure amongst the Arsacid monarchs, who used his name as a royal honorific. By the time of his death, Arsaces had laid the foundations of a strong state, which would eventually transform into an empire under his great-grandnephew, Mithridates I, who assumed the ancient Near Eastern royal title of King of Kings. Arsaces was succeeded by his son Arsaces II.

Literary sources are very scarce on Arsaces, and exclusively come from contradictory Greek and Roman accounts written centuries after his death. As a result, his reign is sparsely known. His existence was even questioned by modern scholars, until new studies and archaeological findings confirmed his identity in the 1960s.

Inscriptional Pahlavi is the earliest attested form of Pahlavi scripts, and is evident in clay fragments that have been dated to the reign of Mithridates I (r. 171–138 BC). Other early evidence includes the Pahlavi inscriptions of Parthian coins and the rock inscriptions of Sasanian emperors and other notables, such as Kartir the High Priest.

Adiabene (Greek: Αδιαβηνή, Classical Syriac: ܚܕܝܐܒ) was an ancient kingdom in northern Mesopotamia, corresponding to the northwestern part of ancient Assyria. The size of the kingdom varied over time; initially encompassing an area between the Zab Rivers, it eventually gained control of Nineveh and starting at least with the rule of Monobazos I (late 1st-century BCE), Gordyene became an Adiabenian dependency. It reached its zenith under Izates II, who was granted the district of Nisibis by the Parthian king Artabanus II (r. 12–40) as a reward for helping him regain his throne. Adiabene's eastern borders stopped at the Zagros Mountains, adjacent to the region of Media. Arbela served as the capital of Adiabene.

The formation of the kingdom is obscure. The first instance of a recorded Adiabenian ruler is in 69 BCE, when an unnamed king of Adiabene participated in the battle of Tigranocerta as an ally of the Armenian king Tigranes the Great (r. 95–55 BCE). However, coinage implies the establishment of a kingdom in Adiabene around 164 BCE, following the disintegration of Greek Seleucid rule in the Near East. Adiabene was conquered by the Parthian king Mithridates I (r. 171–132 BCE) between 145–141 BCE, and served at least from the reign of Mithridates II (r. 124–91 BCE) as an integral part of the Parthian realm.

Phraates II (also spelled Frahad II; Parthian: 𐭐𐭓𐭇𐭕 Frahāt) was king of the Parthian Empire from 132 BC to 127 BC. He was the son and successor of Mithridates I (r. 171–132 BC).

Because he was still very young when he came to the throne, his mother Rinnu initially ruled on his behalf. His short reign was mainly marked by his war with the Seleucid Empire, which under king Antiochus VII Sidetes (r. 138–129 BC) attempted to regain the lands lost to Phraates' father. Initially unsuccessful in the conflict, Phraates II managed to gain the upper hand and defeated Antiochus VII's forces, with the Seleucid ruler himself dying in battle or committing suicide. Phraates II afterwards rushed to the east to repel an invasion by nomadic tribes—the Saka and Yuezhi, where he met his end. He was succeeded by his uncle Artabanus I.

The Parthian Empire (/ˈpɑːrθiən/), also known as the Arsacid Empire (/ˈɑːrsəsɪd/), was a major Iranian political and cultural power centered in ancient Iran from 247 BC to 224 AD. Its latter name comes from its founder, Arsaces I, who led the Parni tribe in conquering the region of Parthia in Iran's northeast, then a satrapy (province) under Andragoras, who was rebelling against the Seleucid Empire. Mithridates I (r. c. 171 – 132 BC) greatly expanded the empire by seizing Media and Mesopotamia from the Seleucids. At its height, the Parthian Empire stretched from the northern reaches of the Euphrates, in what is now central-eastern Turkey, to present-day Afghanistan and western Pakistan. The empire, located on the Silk Road trade route between the Roman Empire in the Mediterranean Basin and the Han dynasty of China, became a center of trade and commerce.

The Parthians largely adopted the art, architecture, religious beliefs, and regalia of their culturally heterogeneous empire, which encompassed Persian, Hellenistic, and regional cultures. The Arsacid court initially adopted elements of Greek culture, though it eventually saw a gradual revival of Iranian cultural traditions. In modern historiography, the Arsacids are considered the first indigenous Iranian dynasty to come to power in the Iranian world after the Achaemenids, in contrast to the Seleucids who represented Hellenistic rule after Alexander the Great. The Arsacid rulers were titled "King of Kings", claiming the inheritance of the Achaemenid Empire; indeed, they accepted many local kings as vassals, though the Achaemenids had centrally appointed, albeit largely autonomous, satraps. The Parthian court appointed a small number of satraps, largely outside Iran, but these satrapies were smaller and less powerful than the Achaemenid potentates. With the expansion of Arsacid power, the seat of central government shifted from Nisa to Ctesiphon along the Tigris (south of Baghdad), although several other sites also served as capitals.