[2] Tarasios had embarked on a career in the secular administration and had attained the rank of senator, eventually becoming imperial secretary (asekretis) to the Emperor Constantine VI and his mother, the Empress Irene of Athens.

[4] Since Tarasios exhibited both Iconodule sympathies and the willingness to follow imperial commands when they were not contrary to the faith, he was selected as Ecumenical Patriarch of Constantinople by Empress Irene in 784, even though he was a layman at the time.

[3] He reluctantly accepted, on condition that church unity would be restored with Rome and the Oriental Patriarchs,[3] and a council be called to address the iconoclast controversy.

[4] To make him eligible for the office of patriarch, Tarasios was duly ordained to the deaconate and then the priesthood, prior to his consecration as bishop.

As a part of his policy of improving relations with Rome, he persuaded Empress Irene to write to Pope Adrian I, inviting him to send delegates to Constantinople for a new council, to repudiate heresy.

His feast day is celebrated on 25 February by the Eastern Orthodox and Byzantine Rite Eastern Catholic Churches (This date on the Julian Calendar at present corresponds to 10 March in common years and 9 March in leap years on the Gregorian Calendar) and on 18 February by Latin Church Catholics.