Mart Mariam Cathedral is the cathedral of the Chaldean Syrian Church of India, part of the Assyrian Church of the East. It is located in Thrissur in the state of Kerala, and is the city's first Christian church.
The church established in 1814 as a Catholic church and was originally known as Our Lady of Dolours Church. It served members of the body now known as the Syro-Malabar Catholic Church, an Eastern Catholic church in communion with the Pope. However, disputes over church hierarchy led part of the community to seek their own autonomous bishop, and in 1874 the Chaldean Catholic bishop Elias Mellus arrived in India and convinced a large part of the Christian community to accept him as their bishop. The group supporting Mellus was based in Our Lady of Dolours. They eventually broke with the Catholic hierarchy and formed the Chaldean Syrian Church.[1] They retained the Our Lady of Dolours building, but renamed it Mart Mariam. In 1929 the Catholics erected a new building, the Basilica of Our Lady of Dolours.
Eventually the Chaldean Syrian Church entered into communion with the Assyrian Church of the East. Mart Mariam now serves as the cathedral.