A unified Kingdom of Georgia reached the peak of its political and economic strength during the reign of King David IV and Queen Tamar in the 11th–12th centuries.
Thereafter the area was dominated by various large empires for centuries, including the Mongols, the Ottoman Empire, and successive dynasties of Iran.
After the Roman Republic completed its brief conquest of what is now Georgia in 66 BC, the area became a primary objective of what would eventually turn out to be over 700 years of protracted Irano-Roman geo-political rivalry and warfare.
In 337 AD King Mirian III declared Christianity as the state religion, giving a great stimulus to the development of literature, arts, and ultimately playing a key role in the formation of the unified Georgian nation, Located on the crossroads of protracted Roman-Persian Wars, the early Georgian kingdoms disintegrated into various feudal regions by the early Middle Ages.
The self-designation used by ethnic Georgians is Kartvelebi (ქართველები, i.e. The medieval Georgian Chronicles present an eponymous ancestor of the Kartvelians, Kartlos, a great-grandson of Japheth.
However, scholars agree that the word is derived from the Karts, the latter being one of the proto-Georgian tribes that emerged as a dominant group in ancient times.
The Kingdom of Georgia reached its zenith in the 12th to early 13th centuries.
This period during the reigns of David IV (called David the Builder, r. 1184–1213) has been widely termed as Georgia's Golden Age or the Georgian Renaissance.
Its root, kartvel-i (ქართველ-ი), specifies an inhabitant of the core central-eastern Georgian region of Kartli, or Iberia as it is known in sources of the Eastern Roman Empire.
The classical period saw the rise of a number of early Georgian states, the principal of which was Colchis in the west and Iberia in the east.