15. DIACONUS. In the Jus Graeco-Romanum of Leunclavius, lib. vi. pp. 395-397, are given Ἐρωτήματα ἅπερ ἔλυσεν ὁ τιμιώτατος χαρτοφύλαξ κύριος Πέτρος, καὶ διάκονς τῆς τοῦ Θεοῦ μεγάλη ἐκκλησίας, ἐν ἔτελ σχ́, Interrogationes quas sol vit reverendissimus Chartularius, Dominus Petrus, idemque Diaconus Majoris Ecclesiae (sc. of St. Sophia at Constantinople) A. M. 6600 = A. D. 1092. We learn from this title that the author lived about the close of the eleventh century in the reign of Alexius I. Comnenus, and that he held the offices described, which is all that is known of him. There are, or were, extant in MS. in the King's Library at Paris, Petrus Diaconus et Philosophus de Cyclo et Indictione, and Petri Diaconi et Philosophi Tractatus de Sole, Luna, et Sideribus (Codd. cmxxix. No. 7. and mmmlxxxxv.), but whether this Petrus Diaconus is the canonist is not clear. (Leaunclav. Jas Gr. Rom. l.c.; Fabric. Bibl. Graec. vol. xi. p. 334; Cave, Hist. Litt. ad ann. 1092, vol. ii. p. 161; Catalog. MSS. Biblioth. Reg. vol. ii. pp. 182, 606, fol. Paris, 1740.)