Kingdom of Armenia (antiquity)

The Kingdom of Armenia also known as Greater Armenia (Armenian: Մեծ Հայք, Mets Hayk), was an Armenian kingdom ruling in the Ancient Near East from 321 BC to 428 AD. It's history is divided into reigns by three royal dynasties: Orontid (321 BC–200 BC), Artaxiad (190 BC–12 AD) and Arsacid (52 AD–428 AD). 
History.
The Kingdom of Armenia was ruled by the Orontid (also known as Yervanduni or Eurandids) dynasty from 321 BC to 200 BC. The Orontids (Eurandids) were an Armenian dynasty of probably Iranian origin. Around 200 BC a coup by the Armenian noble family of Artaxias toppled the Orontid (Yervanduni) dynasty, Thus the Artaxiad dynasty came to power, as depending on the Seleucids. The Artaxiad dynasty was been identified as a branch of the Orontid (Eurandid) dynasty. The Seleucid Empire's influence over Armenia had weakened after it was defeated by the Romans in the Battle of Magnesia in 190 BC. A Hellenistic Armenian state was thus founded in the same year by Artaxias I alongside the Armenian kingdom of Sophene led by Zariadres. Artaxias seized Yervandashat, united the Armenian Highlands at the expense of neighboring tribes and founded the new royal capital of Artaxata near the Araxes River. The new city was laid on a strategic position at the juncture of trade routes that connected the Ancient Greek world with Bactria, India and the Black Sea which permitted the Armenians to prosper.
Tigranes the Great 
After the death of Mithridates II of Parthia his son Gotarzes I succeeded him. He reigned during a period coined in scholarship as the "Parthian Dark Age," due to the lack of clear information on the events of this period in the empire, except a series of, apparently overlapping, reigns. This system of split monarchy weakened Parthia, allowing Tigranes II of Armenia to annex Parthian territory in western Mesopotamia. This land would not be restored to Parthia until the reign of Sinatruces ("r". c. 78–69 BC). In 83 BC, after bloody strife for the throne of Syria, governed by the Seleucids, the Syrians decided to choose Tigranes as the protector of their kingdom and offered him the crown of Syria. He then conquered Phoenicia and Cilicia, effectively putting an end to the last remnants of the Seleucid Empire, though a few holdout cities appear to have recognized the shadowy boy-king Seleucus VII Philometor as the legitimate king during his reign. The southern border of his domain reached as far as Ptolemais. Many of the inhabitants of conquered cities were sent to his new metropolis of Tigranocerta.
Under reign of Tigranes the Great, Kingdom of Armenia stretched from the Caspian Sea to the Mediterranean and the Kingdom of Armenia was called the "Armenian empire" during her reign. At one time, the domains of Tigranes the Great stretched from the shores of the Caspian Sea to the Mediterranean, from Mesopotamia up to the Pontic Alps. The vast empire, formed of a varied mixture of diverse tribes, with their own dialects and cultures, could hardly be turned over- night into a cohesive and durable political structure. Inner disunity aided the designs of the Romans, who launched a series of onslaughts on the Armenian dynast, beginning with the invasion by Lucullus in 69-68 B.C, and culminating in the campaigns of Pompey in Armenia, Iberia and Colchis in 66-65 B.C. The downfall of Tigranes the Great was precipitated by the flight of his son, Tigranes the Younger, to the court of the Parthian king Phraates III, who supplied him with an army with which to invade Armenia, and join forces with the victorious Romans.
Approximately half a century after the collapse of the Artaxiad dynasty Armenia was under the rule of the Arshakunis, the Armenian branch of the Parthian Arsacids. Next, in 314, under King Tiridates (Trdat) the Great and through the apostolate of St. Gregory the Illuminator, Armenia, nearly simultaneously with the Roman empire, officially accepted Christianity, a turning point in its history. An event of importance in the Arshakuni period was the invention, on the threshold of the fifth century, of the Armenian alphabet by St. Mesrop. With this Armenian became the language of the educated; it was introduced into the liturgy; and national literature was born (under Hellenistic and Syrian influences). Armenia’s identity and individuality were thus saved and an absorption by either Byzantine or Iranian civilization was precluded.
The Arsacid dynasty was overthrown by the Sasanid Empire in 428, and this was the end of the Kingdom of Armenia.
Religion.
Until the late Parthian period, Armenia was a predominantly Zoroastrian-adhering land. With the advent of Christianity, both paganism and Zoroastrianism gradually started to diminish. The founder of the Arsacid branch in Armenia, Tiridates I was a Zoroastrian priest or magus. A noted episode which illustrates the observance by the Armenian Arsacids is the famous journey of Tiridates I to Rome in A.D. 65–66. With the adoption of Christianity in the early 4th century, Zoroastrianism's influence in the kingdom gradually started to decline.
Sources.
History.
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