Today 83.4 per cent of the population practices Eastern Orthodox Christianity, with the majority of these adhering to the national Georgian Orthodox Church. The Georgian Orthodox Church is one of the world's most ancient Christian Churches, and claims apostolic foundation by Saint Andrew. In the first half of the 4th century, Christianity was adopted as the state religion of Iberia (present-day Kartli, or eastern Georgia), following the missionary work of Saint Nino of Cappadocia. The Church gained autocephaly during the early Middle Ages; it was abolished during the Russian domination of the country, restored in 1917 and fully recognised by the Ecumenical Patriarchate of Constantinople in 1989.