This paper was read before the Society in 1881, but owing to the difficulty of getting the photographs necessary to illustrate it properly it has not been ready for publication until within the last two years.

In the year 1877 my late friend Dr. Paspati, then resident at Constantinople, published a list and a description of some then unidentified Byzantine churches in Constantinople, the majority of them being used as Mohammedan mosques. In the year 1880 I visited all of them, and among the number a building which Dr. Paspati describes as the Kalender Khane Djami, or the Mosque of the Kalenders.