The Syro-Malabar Catholic Church (, Edtha d'Malabar Suryaya) or Church of Malabar Syrians is an Eastern Catholic Major Archiepiscopal Church in full communion with the Bishop of Rome, the Pope. It is one of the 23 sui iuris Eastern Catholic Churches in the Catholic communion. The Church is headed by Major Archbishop Cardinal George Alencherry of the Archeparchy of Ernakulam-Angamaly in Kerala, India. The members of the Church are known as Mar Thoma Nasranis or Syrian Catholics. It is the largest of the Nasrani denominations with around 4.6 million believers and traces its origins to the evangelistic activity of Thomas the Apostle in the 1st century.