[328] Balsamon, vol. i. col. 501 [Greek: en tô Troullô tou basilikou palatiou]. [329] Theoph. p. 541. [330] Pachym. i. p. 405. [331] _Acta et diplomata Graeca_, iii. p. 65; cf. Paspates, _Great Palace_, p. 248, Metcalfe's translation. [332] _Proceedings of Greek Syllogos of C.P._, Archaeological Supplement to vol. xvii. p. 8. His principal reason seems to be the fact that a company of nuns occupied some of the cells in the old monastery of S. John in Petra when Gerlach visited the city. But, according to Gerlach, another sisterhood was at the same time accommodated in the small convent of S. John the Baptist near the patriarchate.--_Turcograecia_, p. 189. [333] Cf. Paspates, p. 304. CHAPTER XIII THE CHURCH OF S. THEKLA, TOKLOU IBRAHIM DEDÉ MESJEDI In the quarter of Aivan Serai, a few paces to the rear of the Heraclian Wall, stands a small mosque known as Toklou Ibrahim Dedé Mesjedi, the architectural features of which proclaim it at once to be an old Byzantine chapel. There is no decisive tradition in regard to the identity of the building. The Patriarch Constantius is uncertain whether it should be recognised as the church of S. Nicholas or as the church of S. Thekla, two sanctuaries situated in the quarter of Blachernae. It cannot have been the former, inasmuch as the site of that church was near the Holy Well, still venerated by Christians and Moslems,[334] in the area enclosed between the Wall of Heraclius and the Wall of Leo the Armenian, now a picturesque Turkish cemetery. One argument for regarding the building as the church of S. Thekla, in this part of the city, is the striking similarity of its Turkish name Toklou to the Greek name Thekla, rendering it exceedingly probable that the former is a corruption of the latter, and a reminiscence of the original designation of the edifice.[335] Turkish authorities, however, have their own explanation of the name Toklou. In the _Historical and Geographical Dictionary_ of Achmed Rifaat Effendi, we are told that a certain Toklou Dedé was the guardian of the tombs of the companions of Khaled, who took part in the first siege of Constantinople (673) by the Saracens. 'His real name was Ghazi Ismail; Dogulu was his nickname. Now Dogh is the Persian for a drink named Airan (a mixture of curds and water), and he was called Dogulu Dedé because during the siege his business was to distribute that drink to the troops. At his request a Christian church near Aivan Serai was converted into a mosque. The church was formerly named after its founder, Isakias.'[336] Another Turkish explanation of Toklou derives the epithet from the rare Turkish term for a yearling lamb, and accounts for its bestowal upon Ibrahim Dedé as a pet name given in gratitude for his services to the thirsty soldiers engaged in the siege of the city.[337] In keeping with these stories is the tradition that the cemetery in the area between the Walls of Heraclius and Leo V.