MESARITES, GIOVANNI and NICOLAO. - These two brothers distinguished themselves in the religious controversies of the time of the Latin Empire of Constantinople. Giovanni (d. 1207) embraced the monastic state and was appointed by Alexios III as professor of exegesis in the Constantinopolitan school. His brother Nicolao (d. ca. 1216–22), previously deacon of Hagia Sophia, from 1208 referendary of the patriarch of Nicaea, was summoned in 1212 to occupy the metropolitan see of Ephesus.
Giovanni is the author of a commentary on the Psalms, now lost. To Nicolao belong several synodal letters and other writings edited by A. Heisenberg and concerning the disputes of December 1204 between the papal legate Peter of Capua and G. M., that of August 1206 between the Latin patriarch of Constantinople, Thomas Morosini, and N. M., and finally the controversy of December 1212 between the representative of Cardinal Pelagius—probably Pons d’Ilharda—and Nicolao himself. In these disputes, the question of the Roman primacy was addressed, against which the Mesaritai adopted a position of total intransigence, even denying the primacy of the Apostle St. Peter, as well as the procession of the Holy Spirit from the Son. On this subject, the Mesaritai upheld the doctrine of Photius, his explanations of Holy Scripture, and repeated the well-known dialectical argument against the Filioque.