According to tradition, the first person to bring Christianity to India (in 52 CE) was:

According to tradition, St Thomas, one of the twelve apostles of Jesus Christ, brought Christianity to India in 52 CE.

The tradition of St Thomas:

According to the tradition of the Christians of Kerala, St Thomas landed at Muziris (Kodungallur, Kerala) in 52 CE.

He is said to have preached in Kerala and Tamil Nadu, and established seven churches (the "Ezhara Pallikal", seven and a half churches) in Kerala, at places such as Kodungallur, Palayur, Kottakkavu, Kokkamangalam, Niranam, Nilackal and Kollam.

He is believed to have been martyred (killed) in 72 CE at Mylapore, near Chennai.

His tomb is believed to be under the San Thome Basilica in Chennai.

St Thomas Mount in Chennai is associated with his martyrdom.

The community of Christians who trace their origin to him are called "St Thomas Christians" or "Syrian Christians" (because they use the Syriac language in their liturgy).

Other early Christian evidence:

• The "Acts of Thomas", an early Christian text, describes Thomas's mission to India, at the court of an Indo-Parthian king named Gondophares, who ruled in the north-west in the 1st century CE.
• Coins of Gondophares have confirmed that he was a historical ruler.
• In the 4th century, a group of Syrian Christians led by Thomas of Cana is said to have come to Kerala.

Later Christian missions:

• St Francis Xavier, a Jesuit missionary, came to Goa in 1542, with the Portuguese; his body is kept in the Basilica of Bom Jesus in Goa.
• Protestant missionaries came later; the Danish missionaries Bartholomaeus Ziegenbalg and others started work at Tranquebar (Tharangambadi) in 1706.
• William Carey, a Baptist missionary, worked at Serampore (Bengal) from 1800.

Why not the other options?

• ✗St Francis Xavier came much later, in 1542.
• ✗St Paul preached in the Mediterranean world.
• ✗Vasco da Gama was a Portuguese explorer who reached India in 1498.