Yohannan I bar Marta was patriarch of the Church of the East between 680 and 683.
Brief accounts of Yohannan's patriarchate are given in the Ecclesiastical Chronicle of the Jacobite writer Bar Hebraeus (floruit 1280) and in the ecclesiastical histories of the Nestorian writers Mari (twelfth-century), ʿAmr (fourteenth-century) and Sliba (fourteenth-century).
His health was very poor, and he died after sitting for only two years and a few days.
[1] A few more details are supplied by Bar Hebraeus: At this period the catholicus Giwargis died and was succeeded by Yohannan Bar Marta, in the second year of Yazid, son of Muawiya, the king of the Arabs who ruled in Palestine.
After he had fulfilled his office for two years, he died and was succeeded by Hnanishoʿ the Great.