It is said, in the grand tradition of apocrypha, that long, long before Christianity wore the vestments of Rome’s official state religion, the Gospel of Christ arrived in Kerala on a Syrian boat and seeped into its being like tea from a teabag (with due credit to Arundhati Roy’s The God Of Small Things ). Not entirely canonical legend has it that St Thomas the Apostle, a disciple of Iso Misiha (Jesus the Messiah), with a few Syrian families, docked on the shores of Kodungalloor, Kerala in 52 AD. And therefrom begins one of the most fantastic backstories ever devised by immigrants anywhere, which has—with devotedly persistent retelling—entered popular imagination and even crept into school textbooks. The story goes that St Thomas converted a few Brahmins and established seven churches along the Malabar Coast. Historians are not without doubts about this theory. They point out that Kerala’s Aryanisation probably happened much later: in the 7th, 8th and 9th centuries AD. It follow...