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.
During this time Armenia and Pontus were actively expanding at the expense of Rome, taking over its Eastern Mediterranean possessions. However, the success of the anti-Roman alliance did not last long. As a result of the brilliant Roman campaigns of Pompey and Lucullus from the west, and the Parthian invasion from the south, Armenia lost a significant part of its conquests by 65 BC, devolving into a Roman-Parthian dependency. At the same time, the Kingdom of Pontus was completely destroyed by the Romans and all its territory including Colchis were incorporated into the Roman Empire as her provinces. The former Kingdom of Colchis was reorganized by the Romans into the province of Lazicum ruled by Roman legati. The following 600 years of Georgian history were marked by struggle between Rome and Persia(Iran) including Parthians and Sassanids who were fighting long wars against each other for the domination in the Middle East including Syria, Mesopotamia, Armenia, Albania, and Iberia. In the 2nd century AD, Iberia strengthened her position in the area, especially during the reign of King Pharsman II who achieved full independence from Rome and reconquered some of the previously lost territories from declining Armenia. In the early 3rd century, Rome had to give up Albania and most of Armenia to Sassanid Iran. The province of Lazicum was given a degree of autonomy that by the end of the century developed into full independence with the formation of a new Kingdom of Lazica-Egrisi on the territories of smaller principalities of the Zans, Svans, Apsyls, and Sanyghs. This new Western Georgian state survived more than 250 years until in 562 when it was absorbed by the Byzantine Empire.
A second Georgian tribal union emerged in the 13 th century BC on the Black Sea coast under the Kingdom of Colchis in western Georgia. The ancient Greeks knew of Colchis, and it featured in the Greek legend of Jason and the Argonauts, who travelled there in search of the Golden Fleece. Starting around 2000 BC, northwestern Colchis was inhabited by the Svan and Zan peoples of the Kartvelian tribes. Another important ethnic element of ancient Colchis were Greeks who between 1000 and 550 BC established many trading colonies in the coastal area, among them Naessus, Pitiys, Dioscurias, Guenos, Phasis (modern Poti), Apsaros, and Rhizos (modern Rize in Turkey). In the eastern part of Georgia there was a struggle for the leadership among the various Georgian confederations during the 6th – 4th centuries BC which was finally won by the Kartlian tribes from the region of Mtskheta. According to the Georgian tradition, the Kingdom of Kartli (known as Iberia in the Greek-Roman literature) was founded around 300 BC by Parnavaz I, the first ruler of the Parnavazid dynasty.
Between the early 2nd century BC and the late 2nd century A.D. both Colchis and Iberia, together with the neighboring countries, become an arena of long and devastating conflicts between major and local powers such as Rome, Armenia and the short-lived Kingdom of Pontus. In 189 BC the rapidly growing Kingdom of Armenia took over more than half of Iberia, conquering the southern and southeastern provinces of Gogharena, Taokhia and Genyokhiaas, as well as some other territories. Between 120 and 63 BC, Armenia’s ally Mithridate VI Eupator of Pontus, conquered all of Colchis and incorporated it into his kingdom, embracing almost all of Asia Minor as well as the eastern and northern Black Sea coastal areas.
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