Dahae in the context of "Central Asia"

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.

The Parni (/ˈpɑːrnaɪ/; Ancient Greek: Πάρνοι, Parnoi), Aparni (/əˈpɑːrnaɪ/; Ἄπαρνοι, Aparnoi) or Parnians were an East Iranian people who lived around the Ochus (Ancient Greek: Ὧχος Okhos) (Tejen) River, southeast of the Caspian Sea in Central Asia. It is believed that their original homeland may have been what is now southern Russia in Eastern Europe, from where they emigrated with other Scythian tribes. The Parni were one of the three tribes of the Dahae confederacy.

In the middle of the 3rd century BCE, the Parni invaded Parthia, "drove away the Greek satraps, who had then only just acquired independence, and founded a new dynasty", that of the Arsacids.

Hyrcania (/hərˈkeɪniə/; Greek: Ὑρκανία Hyrkanía, Old Persian: 𐎺𐎼𐎣𐎠𐎴 Varkâna, Middle Persian: 𐭢𐭥𐭫𐭢𐭠𐭭 Gurgān, Akkadian: Urqananu) is a historical region composed of the land south-east of the Caspian Sea in modern-day Iran and Turkmenistan, bound in the south by the Alborz mountain range and the Kopet Dag in the east.

The region served as a satrapy (province) of the Median Empire, a sub-province of the Achaemenid Empire, and a province within its successors, the Seleucid, Arsacid and Sasanian empires. Hyrcania bordered Parthia to the east (later known as Abarshahr), Dihistan to the north, Media to the south and Mardia to the west.

The Amardians, widely referred to as the Amardi (and sometimes Mardi), were an ancient Iranian tribe living along the mountainous region bordering the Caspian Sea to the north, to whom the Iron Age culture at Marlik is attributed. They are said to be related to, or the same tribe as, the Dahae and Sacae. That is to say, they were Scythian. Herodotus mentions a tribe with a similar name as one of the ten to fifteen Persian tribes in Persis.

They lived in the valleys in between the Susis and Persis, in what is now southwestern Iran. The southern Mardi are described by Nearchus as one of the four predatory mountain peoples of the southwest, along with the Susians, Uxii, and Elymaeans. Of these four nomadic groups, they were the only tribe linguistically Iranian.