NICOLA il MISTICO. — Patriarch of Constantinople (901–907; 912–25), born around the middle of the ninth century in Byzantine Italy. He was senator and intimate adviser (hence the title “Mystic”) of his predecessor Ant. Caullas. At the beginning of his patriarchate, he maintained good relations with the papacy. When, however, the emperor Leone VI addressed the other patriarchs and Pope Sergio III in order to obtain a dispensation to contract a fourth marriage (after the death of his first three wives), N. showed himself irritated and therefore avoided meeting the ambassadors of Pope Sergio who came to Constantinople in 906. His intransigent conduct was the cause of his deposition, decreed by the Emperor.
The latter, first securing N.’s deed of abdication, elevated his spiritual father Eutimio to the patriarchal see. Eutimio accepted this dignity when he learned of N.’s abdication and became acquainted with the contents of the letters from the other patriarchs and the Pope permitting Leone VI’s fourth marriage. After the death of the latter (912), his successor and brother Alessandro sent Eutimio into exile and recalled N. to the see. During his second patriarchate (912–25), N. wrote several times to Popes Anastasio III and Giovanni X, seeking peace between his own supporters and those who had remained faithful to Eutimio, as well as peace between Byzantium and Rome; and he resumed much of his severity toward the tetragamy of the deceased Emperor. Thus, after various unsuccessful attempts, he obtained from Pope Giovanni X an embassy in 923. The result was beneficial both to internal Byzantine peace and to the
cause of union. N. died on 15 May 925; the Greek Church celebrates his memory on the same day. His 63 letters were edited by Cardinal Mai in 1844 and reproduced in PG 111, 1–406.