According to Orthodox tradition, Christianity was first preached in Georgia by the Apostles Simon and Andrew in the 1st century. It became the state religion of Kartli (Iberia) in 337. The conversion of Kartli to Christianity is credited to St. Nino of Cappadocia. The Georgian Orthodox Church, originally part of the Church of Antioch, gained its autocephaly and developed its doctrinal specificity progressively between the 5th and 10th centuries. The Bible was also translated into Georgian in the 5th century, as the Georgian alphabet was developed for that purpose. As was true elsewhere, the Christian church in Georgia was crucial to the development of a written language, and most of the earliest written works were religious texts. The Georgians' new faith, which replaced pagan beliefs and Zoroastrianism, was to place them permanently on the front line of conflict between the Islamic and Christian worlds. Georgians remained mostly Christian despite repeated invasions by Muslim powers, and long episodes of foreign domination. After Georgia was annexed by the Russian Empire, the Russian Orthodox Church took over the Georgian church in 1811.
The Georgian church regained its autocephaly only when Russian rule ended in 1917. The Soviet regime that ruled Georgia from 1921 did not consider revitalization of the Georgian church an important goal, however. Soviet rule brought severe purges of the Georgian church hierarchy and frequent repression of Orthodox worship. As elsewhere in the Soviet Union, many churches were destroyed or converted into secular buildings. This history of repression encouraged the incorporation of religious identity into the strong nationalist movement and the quest of Georgians for religious expression outside the official, government-controlled church. In the late 1960s and early 1970s, opposition leaders, especially Zviad Gamsakhurdia, criticized corruption in the church hierarchy. After Ilia II became the patriarch (catholicos) of the Georgian Orthodox Church in the late 1970s, Georgian Orthodoxy experienced a revival. In 1988 Moscow permitted the patriarch to begin consecrating and reopening closed churches, and a large-scale restoration process began. The Georgian Orthodox Church has regained much power and full independence from the state since the restoration of Georgia's independence in 1991. It is not a state religion, but its special status is recognized by the Concordat of 2002.
Apart from the Georgian Orthodox Church, Christianity in Georgia is represented by followers of the Armenian Apostolic Church and the Russian Orthodox Church, and a Georgian Catholic Church which mostly follows the Latin Rite.