cross-in-square church
Type of church in which four barrel-vaulted bays form a greek cross; the central square of their intersection is domed. The cross is inscribed into the square ground plan by means of four corner bays.

euchologio
("The prayer book") A liturgical book containing the various services, sacraments and prayers required for ceremonies and services of the Church. The Great Euchologion contains the three Liturgies, while the Minor Euchologion contains sacraments and prayers recuired for the administration of the sacraments.

martyrion
(pl. martyria) Shrine or building over the grave or the place of martyrdom of a martyr.

opus sectile, the
Technique of floor or wall decoration. Thin pieces of polychrome marble are carved or joined so that a decorative motif could be depicted.

praetorian prefect (praefectus praetorio)
Commander of the emperor's bodyguard under the principate. During the regne of Constantine I the praetorian prefect becomes a dignitary responsible for the administrative unit called the prefecture, which was subdivided into dioceses. In 400 A.D. there were four such praetorian prefectures, of Oriens, of Illyricum, of Illyricum, Italia and Africa and of Gallia. The praetorian prefects were second only to the emperor. The praetorian prefect of Oriens was the mightiest among prefects. His office is for the last time mentioned in 680.

synaxarion
A liturgical text containing a short account of the saint's life and acts meant to be read at orthros (the morning liturgy) on the day of the saint's celebration.

Synaxarion of Constantinople
A compilation of brief accounts on every saint that was celebrated during a liturgical year, arranged by months. It was one of the first and most thorough compilation of synaxaria and it is considered a valuable source for the Byzantine studies. Its compilation must be dated to the 10th century and was probably linked to the tradition of the Church of Constantinople. It was the model for many synaxaria compiled later (such as the Menologion of Basil II), and it was completed or slightly altered in some parts through the years. It was published in 1902 by the Belgian scholar Hippolyte Delehaye (Synaxarium ecclesiae Constantinopolitanae e codice Sirmondiano [Bruxelles 1902]).

synaxis
An assembly, especially a monastic or liturgical clerical gathering. Also "synaxis" refers to the special commemorative services celebrated the day following some of the great church's feasts.