Most. Rev. Dr. Devadass Ambrose Mariadoss  was born on 6th  October 1947, to Mariadoss and Ranjitham, a Catholic family from Ammapet, Thanjavur District. After finishing his basic education at Appavu Thevar High School at Ukkadai, he joined St. Mary’s Minor Seminary to become a diocesan priest when the diocese was in a desperate need for the native priests and then he was sent to Sri Pushpam College, Poondi, along with Rt. Rev. F. Antonysamy, the present bishop of Kumbakonam to do Pre-University Course for his secular UG degree, after finishing his secular studies, he was sent to St. Paul’s Seminary, Trichy for his priestly formation and for his Phiur.losophical (B.ph) and Theological studies (B.Th.). Eventually, he was ordained a priest on 5 August 1974 by Rt. Rev. Bishop Arokiasamy Sundaram, the first Bishop of Thanjavur.

Presently, His Holiness, Pope Francis has appointed His Excellency Most Rev. Devdass Ambrose Mariadoss, Bishop of Thanjavur as Apostolic Administrator Sede Vacante of Tiruchirapalli. This ecclesiastical provision was made public in Rome on Saturday, 14th July, 2018, at noon local time, corresponding to 15:30 hours, Indian Standard Time.