The Cause of the Servant of God Devasahayam Pillai is a historical Cause, dealing with a person who lived and died in the 18th Century in India. It is therefore important to prove two points: the martyrdom itself and its fame from the time of martyrdom to our day. The martyrdom has to be proved from the authentic contemporary documents and if available the eye-witness accounts. For the fame of martyrdom, we need documents, living traditions through two and a half centuries and the witnesses for today. We give here briefly the indications of such evidences that are available, to establish without any doubt both the martyrdom as well as the fame of martyrdom up to the present time.