Leontius Bysantinus (Leontios Buzantios), an important theologian of the sixth century. In spite of his deserved fame there are few Christian writers whose lives have been so much discussed. Till quite lately even his period was not considered certain. Bellarmine and Labbe placed him before the fifth general council (Constantinople A. n.553; cf. “Scriptores eceles.”, Venice, 1728, VII, 204). He has been assigned to the time of Gregory the Great (590-604; Mirmus, “Bibl. eccl.”, Antwerp, 1639, 211); identified with Bishop Leontius of Salamis in Cyprus (in the VII cent.; Cave, `Script. eccles. hist. Mt.”, Geneva, 1720, 352); and with the Origenist Leontius mentioned in the “Life of St. Sabas” by Cyril of Scythopolis (Canisius-Basnage, “Thesaurus monum. eccles.”, Antwerp, 1725, 529 and 533). There is, or was, the same uncertainty about his works; the authenticity of many books under his name has been discussed continually. In short, Fabricius said with some reason that (at his time) it was impossible to come to any clear conception of who Leontius really was, or what he really wrote (Fabricius-Harles, “Biblioth. Graeca”, Hamburg, 1802, VIII, 310). In his account of himself, in a work whose authenticity is undisputed (Contra Nest. et Eutych.), he says that in his youth he had belonged to the Nestorian sect, but was converted by “holy men who cleansed his heart by the works of true theologians” (P.G., LXXXVI, 1358 and 1360). Other works (“Adv. Nest.”, and “Adv. Monoph.”) describe him in their title as a monk of Jerusalem (P.G., LXXXVI 1399 and 1769). Friedrich Loofs has made a special study of his life and works. As far as the Life is concerned, his conclusion is accepted in the main by Ehrhard and Krumbacher (Byzant. Litt., 55), Bardenhewer (Patrologie, 506-508), and to some extent Rugamer.
According to Loofs, Leontius was the monk of that name who came with others (Scythian) to Rome in 519, to try to persuade Pope Hormisdas (514-523) to authorize the formula (suspect of Monophysitism)”One of the Trinity suffered”, and was also the Origenist Leontius of the “Vita S. Saba'”. He was born, probably at Constantinople, about 485, of a distinguished family related to the imperial general Vitalian. He then joined the Nestorians in Scythia, but was converted and became a stanch defender of Ephesus. Early in his life he became a monk. He came to Constantinople in 519, and then to Rome as part of the embassy of Scythian monks. After that he was for a time in Jerusalem. In 531 he took part in public disputes arranged by Justinian (527-565) between Catholics and the Monophysite followers of Severus of Antioch (538). He stayed at the capital till about 538, then went back to his monastery at Jerusalem. Later he was again at Constantinople, where he died, apparently before the first Edict against the “Three Chapters” (544). Loofs dates his death at “about 543”. His change of residence accounts for the various descriptions of him as “a monk of Jerusalem” and “a monk of Constantinople“. This theory, explained and defended at length by Loofs, supposes the identification of our author with the “Venerable monk Leontius and Legate of the Fathers (monks) of the holy city (Jerusalem)” who took part in Justinian’s controversy (Mansi, VIII, 818; cf. 911 and 1019); with the Scythian monk Leontius who came to Rome in 519 (Mansi, VIII, 498 and 499); and with the Origenist Leontius of Byzantium, of whom Cyril of Scythopolis writes in his “Life of St. Sabas” (Cotelerius, “Ecclesiae grace monumenta”, Paris, 1686).
Rugamer admits the period of Leontius’s life de fended by Loofs (this may now be considered accepted), and the identification with the disputant at Constantinople (Leontius von Byzanz, 56-58). He thinks his identity with the Scythian monk to be doubtful. Leontius himself never mentions Scythia as a place where he has lived; he does not defend the famous sentence “One of the Trinity suffered” with the ardor one would expect in one of its chief patrons (ibid., pp. 54-56). Rugamer altogether denies the identification with the Origenist Leontius. Had he been an Origenist his name would not be so honored in Byzantine tradition, where he appears as “blessed”, “all-wise”, and “a great monk” (ibid., pp. 58-63). According to Rugamer, Leontius spent his youth and became a Nestorian at Constantinople at the time of the Henoticon schism (482-519). He went after his conversion to Jerusalem and became a monk there. He had never been a public orator, as some authors (Nirschl, “Lehrbuch der Patrologie and Patristik”, Mainz, 1885, p. 553) conclude from the title scholastikos (the common one for such persons; it is often given to him). On the contrary, he shows no special legal or forensic training, and never refers to such a career in his youth. So scholastikos in his case can only mean a learned man. He came to Constantinople for the disputation, went back to Jerusalem, was superior of a monastery there, was an enemy of Theodore of Mopsuestia, but yet did not desire the condemnation of the “Three Chapters“, and died after 553 (op. cit., pp. 49-72).
The works ascribed to Leontius Byzantinus are: (I) three books “Against the Nestorians and Eutychians” (commonly quoted as “Contra Nestorianos et Eutychianos”, P.G., LXXXVI, 1267-1396). This is certainly authentic (in other words, the person about whom they dispute is the author of this work). It is his earliest composition. Book I refutes the opposite heresies of Nestorius and Eutyches, and establishes the Faith of Chalcedon. Book II, in dialogue form, refutes the heresy of the Aphthartodocetes (mitigated Monophysites who made our Lord’s human nature incorruptible during His life on earth—therefore not a true human nature). Book III (the title of this book in Migne belongs really to Book II) accuses the Nestorians of dishonest practices to make converts, and vehemently attacks Theodore of Mopsuestia. The whole work is full of well-selected quotations from the Fathers, and shows great learning and controversial skill. All the other works have been disputed, at least in their present form. (2)”Against the Monophysites” (“Adv. Monophysitas”, P.G., LXXXVI, 1769-1902), in two parts, but incomplete. Part I argues philosophically from the idea of nature; part II quotes the witness of the Fathers, and refutes texts alleged to favor Monophysitism. (3)”Against the Nestorians” (“Adv. Nestorianos”, P.G., LXXXVI, 1399-1768), in eight books, of which the last is wanting. “A classical work” (Nirschl, op. cit., 555), explaining and defending all the issues against this heresy. Book IV defends the title Theotokos; book VII defends the formula: “One of the Trinity suffered”. (4)”Scholia”, or “Of Sects” (“De Sectis”, P.G., LXXXVI, 1193-1268); ten chapters called “Acts” (praxeis) against all the known heretics at that time, including Jews and Samaritans. (5)”Solution of the arguments proposed by Severus” (of Antioch; “Adv. Severum”, G., LXXXVI, 1915-46). A refutation of Monophysitism in dialogue form. It supposes a Monophysite work (otherwise unknown) whose order it follows. (6)”Thirty chapters against Severus” (“Triginta capita”, P.G., LXXXVI, 1901-16), a short work with many parallels to the preceding one. (7)”Against the frauds of the Apollinarists” (“Adv. fraudes Apollinaristarum”, P.G., LXXXVI, 1947-76), a very important work, the beginning of the discovery of the works of Apollinaris of Laodicea which still occupies the minds of students. It is an examination of certain works attributed to Athanasius, Gregory Thaumaturgus, and Pope Julius, which are declared to be really by Apollinaris, and fraudulently attributed to these Fathers by his followers. (8)”Discussions of Sacred Things”, by Leontius and John (“De rebus sacris”, P.G., LXXXVI, 2017-2100). This is a recension of the second book of the “Sacra Parallela” (collections of texts of the Fathers) of which a version is also attributed to St. John Damascene (c. 760). (9) Two homilies by a priest Leontius of Constantinople (P.G., LXXXVI, 1975-2004), certainly another person. Of these works, (I) is certainly genuine, (8) and (9) are certainly not. The “De rebus sacris” was probably composed between 614 and 627. The Leontius of the title is a bishop of that name of Salamis in Cyprus. Of the others, Loofs thinks that (5) and (6) are fragments of a large work by Leontius Byzantinus, called “Scholia”; (2), (3), and (4) are later works founded on it. (7) is by another (unknown) author, written between 511 and 520. Rugamer, on the other hand, defends the authenticity in their present form of all these works, except (8) and (9).
Leontius of Byzantium is, in any case, a theologian of great importance. Apart from the merit of his controversial work against Nestorians and Monophysites, his Aristotelianism marks an epoch in the history of Christian philosophy. He has been described as the first of the Scholastics (Krumbacher-Ehrhard, “Byzantinische Litteratur”, p. 54).