The belief is that St Thomas, the disciple of Jesus Christ who came to India in 52 AD, landed in the port town of Kadungalloor and established a Christian community there. Later a group of Syrian Christians led by Thomas of Cana landed in Kodungalloor between 4th and 9th century. Emperor Cheraman Perumal welcomed them and gave all help to the expatriates for settlement. They opened and operated the famous Mahadevar Pattanam a market town. The expatriates were rich people and by the business became more rich. Thomas of Cana led a group of 72 families, as well as clergymen, to the Malabar Coast. There they met and supplemented the Saint Thomas Christians, who had been evangelized by Thomas the Apostle in the 1st century. Copper plates referring to this story exist, but are of a substantially later date. During the war, Mahadevar Pattanam was destroyed and many expatriates family moved down to Travancore.
Thachil Illam was one of the famous Brahmin Tharavad in Kerala. Thachil Brahmins were chief priests in the Thirumoozhikkulam Temple. They were converted to Christianity and migrated to Kuthiathode. Some believe that they were converted to Christianity by Thomas of Cana (Knai Thomman). Thachil Variyath is the Grand father of Thachil family who migrated to North Kuthiathode.
Thachil Family Book published by the efforts of Chevalier Lona Vareed provides in depth history and details of Thachil family up to 10 generations. This book provides family tree information starting from 1650 AD.
Its estimated to be more than 3000 Thachil families spread all over the world. There is around 250 Thachil familes live in North Kuthiathode alone.