Iberia (Georgian — იბერია, Latin: Iberia or Iberi and Greek: Ἰβηρία), also known as Iveria (Georgian: ივერია), was a name given by the ancient Greeks and Romans to the ancient Georgian kingdom of Kartli (4th century BC-5th century AD). The term Caucasian Iberia (or Eastern Iberia) is used to distinguish it from the Iberian Peninsula, where the present day states of Spain and Portugal are located. The Caucasian Iberians provided a basis for later Georgian statehood and along with Colchis (early western Georgian state) formed a core of the present day Georgian people (or Kartvelians).
The area was inhabited in earliest times by several relative tribes, collectively called Iberians (the Eastern Iberians) by ancient authors. Locals called their country Kartli after a mythic chief, Kartlos.
The Moschi mentioned by various classic historians, and their possible descendants, the Saspers (who were mentioned by Herodotus), may have played a crucial role in the consolidation of the tribes inhabiting the area. The Moschi had moved slowly to the northeast forming settlements as they traveled. The chief of these was Mtskheta, the future capital of the Iberian kingdom. The Mtskheta tribe was later ruled by a principal locally known as mamasakhlisi (“the father of the household” in Georgian).
The medieval Georgian source Moktsevai Kartlisai (“Conversion of Kartli”) speak also about Azo and his people, who came from Arian-Kartli - the initial home of the proto-Iberians, which had been under Achaemenid rule until the fall of the Persian Empire - to settle on the site where Mtskheta was to be founded. Another Georgian chronicle Kartlis Tskhovreba (“History of Kartli”) claims Azo to be an officer of Alexander’s, who massacred a local ruling family and conquered the area, until being defeated at the end of the 4th century BC by Prince Pharnavaz, who was at that time a local chief.
Pharnavaz, victorious in power struggle, became the first king of Iberia (ca. 302-ca. 237 BC). Driving back an invasion, he subjugated the neighbouring areas, including significant part of the western Georgian state of Colchis (locally known as Egrisi), and seems to have secured recognition of the newly founded state by the Seleucids of Syria. Now Pharnavaz focused on social projects, including the citadel of the capitol, the Armaztsikhe, and the idol of the god Armazi. He also reformed the Georgian written language, and created a new system of administration subdividing the country in several counties called saeristavos. His successors managed to gain control over the mountainous passes of the Caucasus with the Daryal (also known as the Iberian Gates) being the most important of them.
The period following this time of prosperity was one of incessant warfare though. Iberia was forced to defend against numerous invasions into their territories. Iberia lost some of its southern provinces to Armenia, and the Colchian lands seceded to form separate princedoms (sceptuchoi). In the end of the 2nd century BC, the Pharnavazid king Farnadjom was dethroned by his own subjects and the crown given to the Armenian prince Arshak who ascended the Iberian throne in 93 BC, establishing the Arshakids dynasty.
This close association with Armenia brought upon the country an invasion (65 BC) by the Roman general Pompey, who was then at war with Mithradates VI of Pontus, and Armenia; but Rome did not establish her power permanently over Iberia. Nineteen years later, the Romans again marched (36 BC) on Iberia forcing King Pharnavaz II to join their campaign against Albania.
While another Georgian kingdom of Colchis was administered as a Roman province, Iberia freely accepted the Roman Imperial protection. A stone inscription discovered at Mtskheta speaks of the first-century ruler Mihdrat I (AD 58-106) as "the friend of the Caesars" and the king "of the Roman-loving Iberians." Emperor Vespasian fortified the ancient Mtskheta site of Arzami for the Iberian kings in 75 AD.
The next two centuries saw a continuation of Roman influence over the area, but by the reign of King Pharsman II (116 – 132) Iberia had regained some of its former power. Relations between the Roman Emperor Hadrian and Pharsman II were strained, though Hadrian is said to have sought to appease Pharsman. However, it was only under Hadrian's successor Antoninus Pius that relations improved to the extent that Pharsman is said to have even visited Rome, where Dio Cassius reports that a statue was erected in his honor and that rights to sacrifice were given. The period brought a major change to the political status of Iberia with Rome recognizing them as an ally, rather than their former status as a subject state, a political situation which remained the same, even during the Empire's hostilities with the Parthians.