Leo DIACONUS
13. DIACONUS or the DEACON, a Byzantine historian of the tenth century. What little is known of his personal history is to be gleaned from incidental notices in his principal work, and has been collected by C. B. Hose in the Praefatio to his edition of Leo. Leo was born at Caloe, a town of Asia, beautifully situated on the side or at the foot of Mount Tmolus, near the sources of the Cäystrus, in Asia Minor. He was the son of Basilius, but his father's condition or calling is not known. (Leo Diac. Historiae, 1.1.) The young Leo was at Constantinople, pursuing his studies, A. D. 966, when he was an admiring spectator of the firmness of the emperor, Nicephorus II. Phocas, in the midst of a popular tumult (4.7.) As he describes himself as a youth (μειρόκιον) at the time of this incident, Hase places his birth in or about A. D. 950. He was in Asia about the time of the deposition of Basilius I., patriarch of Constantinople, and the election of his successor Antonius III., A. D. 973 or 974, and relates that at that time he frequently saw two Cappadocians, twins, of thirty years old, whose bodies were united from the armpits to the flanks (10.3). Having been ordained deacon, he accompanied the emperor Basilius II. in his unfortunate campaign against the Bulgarians, A. D. 981; and when the emperor raised the siege of Tralitza or Triaditza (the ancient Sardica), Leo narrowly escaped death or captivity in the headlong flight of his countrymen (10.8). Of his history after this nothing is known; but Hase observes that he must have written his history after A. D. 989, as he adverts to the rebellion and death of Phocas Bardas (10.9), which occurred in that year. Both this event and the Bulgarian campaign are noticed by him by anticipation, in a digression respecting the evils which he supposed were portended by a comet which appeared just before the death of Joannes I. Tzimisces. He must have lived later than Hase has remarked, and at least till A. D. 993, as he notices (10.10) that the emperor Basilius II. restored "in six years" the cupola of the great church (St. Sophia) at Constantinople which had been overthrown by the earthquake (comp. Cedren. Compend. vol. ii. p. 438, ed. Bonn) of A. D. 987.
Works
The works of Leo Diaconus comprehend 1. Ἱστορία Βιβλίοις ύ, Historia Libris decem 2. Oratio ad Basilium Imperatorem 3. (unless it be the work of another Leo Diaconus) Homilia in Michaelem Archangelum The two last are extant only in MS.
Ἱστορία Βιβλίοις ύ, Historia Libris decem
The history of Leo includes the period from the Cretan expedition of Nicephorus Phocas, in the reign of the emperor Romanus II., A. D. 959, to the death of Joannes I. Tzimisces, A. D. 975. It relates the victories of the emperors Nicephorus and Tzimisces over the Mohammedans in Cilicia and Syria, and the recovery of those countries, or the greater part of them, to the Byzantine empire; and the wars of the same emperors with the Bulgarians and Russians. The style of Leo is described by Hase as vicious: he employs unusual and inappropriate words (many of them borrowed from Homer, Agathias, the historian, and the Septuagint), in the place of simple and common ones; and abounds in tautological phrases. His knowledge of geography and ancient history is slight; but with these defects his history is a valuable contemporary record of a stirring time, honestly and fearlessly written. Scylitzes, and through him Cedrenus, are much indebted to Leo; and Hase considers Zonaras also to have used his work.
Editions
The Historia was first published, at the cost of count Nicolas Romanzof, chancellor of Russia, by Car. Bened. Hase, Paris, 1818. Combéfis had intended to publish it in the Parisian edition of the Corpus Historiae Byzantinae with the Historia of Michael Psellus, but was prevented by death, A. D. 1679. The Latin version which he had prepared was communicated by Montfaucon to Pagi, who inserted some portions in his Critice in Baronium (ad ann. 960, No. ix). The papers of Combéfis were, many years after, committed to Michael Le Quien, that he might publish an edition of Psellus and Leo, and part of the latter author's work was actually printed; but the breaking out of the war of the succession (A. D. 1702) prevented its completion, and Hase could find no trace of the part printed. In the disorders of the French revolution the papers of Combéfis were finally lost or destroyed. Hase in his edition added a Latin version and notes to the text of Leo, and illustrated it by engravings from ancient gems. His edition is, however, scarce and dear, the greater part of the copies having been lost by shipwreck; but his text, preface, version, and notes (not the engravings), have been reprinted in the Bonn edition of the Corpus Historiae Byzantinae. 8vo. 1828.
Further Information
Fabric. Bibl. Graec. vol. vii. p. 684, note 1; Cave, Hist. Litt. vol. ii. p. 106; Hase, Praefatio ad Leon. Diacon. Historiam.
From William Smith (ed.), Dictionary of Greek and Roman Biography and Mythology. Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities and Tufts University. Data accessed from https://github.com/PerseusDL/canonical-pdlrefwk/ on 17 October 2026.