endemousa synodos (permanent synod) of Constantinople
A consulting synod of ecclesiastic officials dwelling in Constantinople, convened every year in the capital to discuss current matters, the demands of bishops and prelates etc.

exarch
At the Byzantine ecclesiastical administration the exarch, from the 5th century onwards, was the head of an ecclesiastical province and later became another title of the Ecumenical Patriarch, certifying that he was the head prelate within the jurisdiction of the Ecumenical Patriarchate. The office of exarch was abolished during the 6th century, although exarchs were metropolites or representatives of metropolites who supervised the ecclesiastical provinces or the ecclesiastical and monastic foundations. During the late 14th century as exarchs are referred the metropolites who were located at ancient dioceses and supervised all the ecclesiastical sees and the charitable institutions of the ecclesiastical province and later the authorized representatives of the Patriarch (patriarchal exarchs).

Fourth Ecumenical Council (Chalcedon, 451)
The Fourth Ecumenical Council assembled in 451 at Chalcedon in order to retract the interpetation of the council of Ephesus (449) on the nature of Jesus Christe.

Terminalia
Roman festival on the 23rd of February honoring god Terminus protector of the boundaries.