St. Thomas, one of the twelve Apostles of Jesus Christ brought the Good News of God's Salvation to India.
We have quite a few evidences to believe that St. Thomas preached the Gospel on the East and West coast of South India especially in Madras (Chennai) and in the city of Kollam (Quilon) (pronounced Koy-lon[1]) in the present State of Kerala.
The Padruado Missionaries by their able leadership and dedicated service led this diocese towards the omega point i.e., "Christ" by bringing many more souls to the Catholic Church.
With his motto "Cor Jesu et Mariae spes mea" and with his special gifts for masterly planning and efficient administration, Sundaram began to build the diocese from scratch.
His successor P. Arokiaswamy (called Archbishop) took charge on 26 November 1986 and continued to lead the diocese to realize her goal.
At present, the Diocese has 184 priests among whom nine are retired and the others are working in the vineyard of the Lord with full vigour and zeal.
They include the Salesians, Carmelites (OCD), Missionaries of St. Francis De Sales (MSFS) and Sacred Heart Brothers.
The pastoral activities in the diocese is vibrant with many independent commissions for Bible, liturgy, catechism, youth animation, social communication, ecumenism & dialogue with non-Christians, etc.
It is worth to note that at present the diocese is experiencing a remarkable spiritual renewal and greater participation of the laity in her life and ministry.
In the sixteenth century, Our Lady appeared to a lame boy in Vailankanni and saved some Portuguese sailors when they were caught in a storm.