and a treatise "On the Names of God" in thirteen chapters, have been the chief source of Christian mystical theology. The first reference to these writings occurs in A.D. 532, when the claim was made that they were the work of Dionysius, the Areopagite, a pupil of St. Paul, or at least represent his teaching. In several places the writer cites Hierotheus as his teacher, and this enables us to identify the source as a Syrian monk named Stephen Bar Sudaili, who wrote under the name of Hierotheus (cf. Asseman, Bibl. Orient. ii. 290–291). This Bar Sudaili was abbot of a convent at Edessa, and was involved in controversy with James of Sarugh, so that we may refer the writings to the latter part of the 5th century A.D. They were translated into Syriac very soon after their first appearance in Greek, and, as familiar to Syriac Christians, must have become indirectly known to the Muslims. We have no direct evidence as to their translation into Arabic, but Mai gives fragments of other works of Bar Sudaili which appear in Arabic MSS. in his Spicilegium Romanum (iii. 707). The traditional view of the relations between Sufism and philosophy is described in the anecdote cited by Prof. Browne (Lit. Hist. of Persia, ii. 261, from Akhlag-i-Jalali) of the Sufi Abu Sa'id b. Abi l-Khayr (d. 441 A.H. = 1049 A.D.), who is said to have met and conversed with Ibn Sina; when they parted Abu Sa'id said of Ibn Sina, "What I see, he knows," whilst Ibn Sina said, "What I know, he sees."
