Given the many Roman coins and Greek amphorae found in the region, it seems rather likely that St (“Doubting”) Thomas did in fact ride the steady monsoon wind to southern India some 15 years after the Crucifixion, founding several churches in Kerala state and meeting his end at spear-point while praying atop St Thomas Mount, in Madras.

If true, this is an important attestation of Jesus’s inspirational powers, for, with the exception of glimpses in Acts and Paul’s letters (notably the interestingly equivocal Galatians ii) the doings of the Twelve (or Eleven) rather disappear after AD30.

Christianity flourishes in southern India. In Madras, St Mary’s, the oldest surviving British church, is faded Raj with memorials to long forgotten native regiments. But at the vermilion Sacred Heart, Pondicherry, the Tamil-speaking priest daily gives his capacity congregation a hard time. After the service, Bible-class children hand in their written work. The church of the Immaculate Conception is magnificent in white and gold.

On the east coast the vast white basilica of Our Lady of Good Health at Velankanni commemorates a Lourdes-like revelation, and is a pilgrimage site. On the day when the tsunami struck there were 20,000 pilgrims at Velankanni, of whom about 2,000 perished along with many more local people. Nowadays, about 1,000 pilgrims each weekend make the 1,100km round trip by coach from Cochin. Mass is celebrated in Telugu, Tamil, Malayalam, English or Hindi, depending on the time of day.

A quarter of the population of Kerala is Christian. Across the peninsula, there is an astonishing number of churches, some derelict, but many imaginatively architectured and gaily coloured. To cater for everybody, Mass is often conducted twice on Sundays.

Christian private schools have a fine reputation — if one can afford the fees at about 300 rupees (or £4) a month. Children of all denominations, often walking long distances, seem cheerful and focused, wearing their varicoloured school uniforms, neatly and with pride.

Of course, the polytheistic mindset that sees the sacred in everything remains a vital part of Hindu culture in the region. Arriving at Madras airport, the traveller is greeted at baggage collection by a large mural depicting the mythic warrior Arjuna confronting an enemy in his chariot.

His charioteer happens to be the god Krishna, who deals with Arjuna’s moral misgivings (and ours): “Do your duty and expect nothing from it” — note “and”, not “but” — the second phrase is equally a philosophical directive.

Most of Hindu philosophy is pre-Christian. Tamil Nadu is Shiva country — Shiva, the Lord of the Dance, is associated with destruction and rebirth. Many of the temples across the state are amazing. The 13-storey gopuram, or main tower, of the 1,000-year-old Brihadishwara temple at Thanjavur, a World Heritage site built by Chola kings about AD1010, is topped by an 80-tonne dome carved from a single rock. Hinduism may not have “services” as such but it certainly has festivals, parades and pilgrimages, attended by hundreds of thousands. Hindus perform their rites as individuals.

The Tamil Nadu temples are well attended; some shrines attract long queues at certain times of day. In the evening, perhaps, the golden doors of a holy place will be thrown open and the people will be allowed a face-to-face encounter with the statue, or perhaps a Shiva lingam, while Brahmin priests are busy with flaming torches and observances. The idol may be anointed daily with quantities of milk.

The museums now hold the best of the Chola bronzes (some recently to be seen at the Royal Academy in London), which are of a sublime beauty.

With crossed palms, right above left for a well-known Asiatic reason, one may be given a blob of ash that will also be used to anoint the forehead in Ash Wednesday style — “dust we are and to dust we shall return”.

Hindus learn the myths of the Ramayana at their mother’s knee, together with the propensities of the innumerable gods and goddesses of the pantheon, recognising that everything is a temple to Bramah, the creator of all.

Guy Liardet is a retired naval officer