This thesis is specially concerned with the section of the Church now called Mar Thoma Syrian Church; it has therefore to leave out of consideration the various groups which live apart from that section, once the occasions of separation have been noticed. Thus we shall see that the Syrian Church has a loose-knit unity until 1653; for the last fifty years that period under Roman Control. Then about half of the Christians became Jacobite in allegiance. The work of the Christian Missionary Society, missionaries in the nineteenth century, led the coversion of a few families to the Anglican faith and the formation of the Mar Thoma Syrian Church. We shall see more about this Church later on in this thesis.