Patriarch of the Church of the East
d. 4th century
21st Catholicos of the East (Seleucia-Ctesiphon) · c. 421–c. 456
Mar Dadishoʿ was the Catholicos of the East from 421 AD to 456 AD. During his reign as Catholicos, in 424 AD, the Church of the East declared itself independent of all other churches, resulting in Mar Dadishoʿtaking the title of Patriarch, becoming the first Catholicos-Patriarch of Seleucia-Ctesiphon.