After the death of Theodora we have only occasional glimpses of the church and monastery. In 1350 Stephen of Novgorod came 'to kiss' the relics of S. Andrew of Crete, and describes the convent as 'very beautiful.'[170] Once, at least, a sister proved too frail for her vocation;[171] sometimes a devout and wealthy inmate, such as Theognosia,[172] would provide an endowment to enable poor girls to become her heirs in religion; or the sisterhood was vexed by the dishonesty of parties who had rented the lands from which the convent derived its revenues.[173] Towards the end of its Byzantine period another Russian pilgrim[174] came to honour the remains of S. Andrew the Strategos, and bring the Christian history of the church to a close. It was converted into a mosque by Mustapha Pasha, Grand Vizier in the reign of Selim I. (1512-1520).[175] The custom of illuminating the minarets of the mosques on the eve of the Prophet's birthday was introduced first at this mosque.[176] _Architectural Features_ On account of the serious changes made in the building and its surroundings when it became a mosque, and after the earthquake of 1765, its real character is not immediately apparent. The present entrance is in the northern side, where a fine Turkish arcade has been erected. The mihrab is on the south side, a greater change for the correct orientation of a mosque than is usually necessary in the adaptation of a church to the requirements of a sanctuary in which the worshippers turn towards Mecca. To the east a hall has been added for the accommodation of women who attend the services; while on the west is another hall, where the dervishes of the Teké attached to the mosque hold their meetings. The north aisle also has been much altered and is covered with Turkish domes. The first impression produced by the interior of the building is that we have here a church on the trefoil plan, similar to S. Mary of the Mongols (p. 272) or S. Elias of Salonica, for the central area is flanked by two semi-domes, which with the eastern apse form a lobed plan at the vaulting level. A closer examination of the building, however, will prove that we are dealing with a structure whose original features have been concealed by extensive Turkish alterations, and that the trefoil form is a superficial disguise. The arches supporting the central dome on the north and south sides are filled in with semi-domes which rest on arches thrown diagonally across the 'aisles' on each side of the central dome. These arches are very clumsily set to the sides of an irregular hexagon, with the central wall arch much larger than the side arches. They have no responds, and have every appearance of being makeshifts.