 Their traditional belief that their ancestors were high-caste Hindus such as Nambudiris and Nairs, who were evangelised by St. Thomas, has also supported their upper-caste status.With the arrival of European missionaries and their evangelistic mission among the lower castes in Kerala, two new groups of Christians, called Latin Rite Christians and New Protestant Christians, were formed but they continued to be considered as lower castes by higher ranked communities, including the Saint Thomas Christians.Caste system has been observed among Muslims in India.