Armenia is one of the oldest countries in the world with a recorded history
of about 3500 years. The oldest known ancestors of modern Armenians, the
Hayasa-Azzi tribes, also known as Proto-Armenians, were indigenous to the
Armenian Highland in Eastern Anatolia. These tribes formed the Nairi tribal
union, which existed until late 13th century BC. The legendary forefather of
Armenians, Hayk, famous for his battles with Babylonian ruler Bel, most likely
was one of the Hayasa tribal leaders. The words 'Nairi' and 'Nairian' are still
used by Armenians as poetic synonyms of the words 'Armenia' and 'Armenian'.
At the end of the second millennium BC, another Indo-European ethnic group, closely related to Thracians and Phrygians and referred to by the Greeks as Armens, migrated to the Armenian Highland from Northern Balkans. According to a Greek myth, which actually reflects this tribal migration, the forefather of Armenians - Armenios - was one of the Argonauts, accompanying Jason in his quest for the Golden Fleece. In the year 1115 BC, king Tiglath Pileser I of Assyria reports a battle with a force of 20,000 Armens in the Gadmokh province of Assyria.
The mixture of Armens with the indigenous Hayasa eventually produced the Armenian people as it is known today. The existence of two major segments in the Armenian people is best of all illustrated by the fact that Armenians call themselves "Hay" and their country "Hayastan" after Hayasa, while other peoples call them Armenians and their country Armenia after the Armens. The Armenian language is basically the language of Armens, which is the only survivor of the now extinct Thraco-Phrygian group. It incorporated a large number of Hayasa words and grammatical features, as well as a significant number of non-Indo-European words from minor ethnic groups, which also took part in the ethnogenesis of Armenians.
The first significant state of the Armenian Highland was the highly advanced Kingdom of Ararat (with the capital in Tushpa, today's Van), better known under its Assyrian name Urartu (Ararat). This state was formed in the XI century BC and existed until VII century BC. Although populated mostly by Armenians, Urartu was ruled (at least during the first centuries) by a non-Armenian and non-Indo-European dynasty. In 782 BC the Urartian king Argishti I founded the fortified city of Erebuni, which is today's Yerevan, the capital of Armenia. Another major city in the Valley of Ararat was Argishti-khinili, also founded by Argishti I in the year 775 BC.
In the late VII century BC Urartu, weakened by Scythian invasions, fell, but after several decades was revived under the Armenian Yervanduni (the Orontides) dynasty with the capital in Armavir, former Argishti-khinili. The revived kingdom was already called Armenia by its neighbours, but in some languages the older name, Urartu, was still in use. In the famous tri-lingual Behistun inscription of Persian king Darius the Great (522-486) the same country is referred to as 'Armenia' in the Persian and Elamite versions, and 'Urartu' in the Akkadian version.
Source: United Nations (Official Site)