The mosque known as Kefelé Mesjedi, in the quarter of Salma Tomruk, is commonly supposed to represent the monastery founded by Manuel,[429] a distinguished general in the wars with the Saracens during the reign of Theophilus (823-842). This opinion is doubtless based upon the circumstance that the monastery in question stood in the vicinity of the cistern of Aspar,[430] [Greek: synengys tê kisternê tou Asparos] (the large open reservoir to the east of the Gate of Adrianople), near which Kefelé Mesjedi is also situated. But that circumstance alone cannot be regarded as sufficient ground for the identification of the two buildings. There are at least five other monasteries mentioned in Byzantine history, all distinguished by the mark of their proximity to the cistern of Aspar.[431] And at a short distance to the west of Kefelé Mesjedi, and nearer to the cistern of Aspar, we find the remains of an old church, now Odalar Mesjedi, which might with equal force claim to represent the monastery of Manuel. The commonly received identification may, however, be correct as a happy conjecture. Mr. Siderides,[432] indeed, considers the identification of the monastery of Manuel with Kefelé Mesjedi a mistake. According to him, that monastery was a reconstruction or enlargement of the ancient monastery of SS. Manuel, Sabel, and Ishmael, which stood on the heights above the Phanar, now crowned by the mosque of Sultan Selim. To the objection that there it would not be near the cistern of Aspar, Mr. Siderides replies by denying the correctness of the identification of that cistern with the open reservoir (Tchoukour Bostan) to the east of the gate of Adrianople, and in the vicinity of Kefelé Mesjedi. In Mr. Siderides' opinion the cistern of Aspar is the beautiful covered cistern, generally known as the cistern of Puicheria, to the south-west of the mosque of Sultan Selim.[433] But the dimensions of the cistern ascribed to the famous sister of Theodosius II. do not accord with the size of the cistern of Aspar. The latter was 'a very large cistern,' [Greek: tên megistên kinsternan],[434] while the former is only m. 29.1 long by m. 18 wide, with a roof supported on four rows of seven columns[435]--not a large cistern as works of that class went in Constantinople. But if the cistern of Aspar was not situated in the district now marked by the mosque of Sultan Selim, neither could the monastery of Manuel have been there. Mr. Siderides,[436] moreover, identifies the monastery of Manuel with that of Manoueliou [Greek: tou Manouêliou] which appears in the Proceedings of the Synod held at Constantinople in 536 under Justinian.[437] This, however, does not agree with the statement that the monastery of Manuel was originally the private residence of the well-known general of that name in the ninth century. Furthermore, it is always dangerous to assume that the same name could not belong to different buildings, especially when the name occurs at distant