The biggest of all the caves must have served as the anchorites' church. It has an elaborately carved doorway with bas-relief panels over it representing apparently the Nativity and the Descent into Hades. The interior is irregularly quadrilateral, and must measure about thirty-five feet across. It has a flat ceiling, and is partly surrounded by a gallery, about eight feet wide and eight feet below the ceiling, supported on a range of rock-cut corbelled arches. There is nothing to indicate the position of the altar, and the eastern side is occupied by the doorway; but the altar may have stood in the centre of the floor. The level of the floor itself is also a matter for conjecture, as at present it is deeply covered with débris. The place is now used as a sheep shelter, and is known as the _khan_ or "Inn." It is lit by a single small window immediately over the door. There is interest enough at Dara to occupy an archæologist for weeks together--for months if he sees fit to excavate--but we had to resume our journey, and we knew that if we wanted more archæologizing we should have no difficulty whatever in finding opportunity on the road. About three hours eastward of Dara stands another Roman fortalice--a big square castle standing in lonely grandeur amid the desolate plain. The walls are now sadly shattered, excepting the great round bastion which is planted at one of the angles; and within the ruined enclosure is hutted a squalid community of miserable half-naked Kurds. This is doubtless the castle between Nisibis and Daras which Justinian ordered to be built in the first year of his reign. It was not auspiciously founded, for Kobad's army descended upon the builders before the work was completed, and the Romans were crushingly defeated, leaving most of their commanders[35] on the field. The future course of the war was, however, more favourably influenced by the fact that a certain junior general, of the name of Belisarius, escaped. Another three hours of slow progress, and we find ourselves approaching another township. The first indication of its neighbourhood is the apparition of a cobble-paved causeway, which gradually consolidates itself out of the dust of the desert, and holds its course steadily onward in a straight undeviating line. Probably it too is Roman, and if so the Romans were the last people who troubled to repair it; for it is so appallingly bumpy, and so frequently intersected by irrigation ditches, that the vehicles tactfully ignore it and keep to the unpaved ground. It leads us at length to a village which is somewhat larger than Dara, but which lacks all Dara's evidences of bygone wealth and grandeur. This place boasts a _khan_ and a market, and is the seat of a local governor. But if it has not fallen so low as its neighbour, it has fallen infinitely farther: for this wretched hamlet is Nisibis, once the impregnable fortress which marked the furthest limit of the power of Imperial Rome.