Half-an-hour’s ride brought us on the following morning to the northern limit of Sâmarrâ. In the angle between the Tigris and the Nahrawân canal lie the remains of Mutawakkil’s tragic palace, built in a year, inhabited for nine months, destroyed and deserted, together with all the quarter round it, when Muhammad el Muntaṣir caused the khalif his father to be murdered within its walls. Immediately beyond it we crossed the dry channel of the Nahrawân, which was cut by the Sassanian kings in order to bring water to the fertile regions below Sâmarrâ (Fig. 125). At the point where our path crossed it are the brick foundations of a bridge, below a large artificial mound.[123] The dry bed of the canal, hewn for scores of miles, straight as a Roman road, through the solid rock, is as impressive as the most magnificent of ruins; for the king who could bid rivers to flow and crops to spring in the barren wilderness was indeed lord of the earth. As we reached the village of Dûr, an hour further to the north, we met a number of the inhabitants coming out along the road, and all were armed with rifles. We stopped and asked them whither they were bound, and they in turn inquired of us whether we had seen anything of a caravan of merchandise from Sâmarrâ. It was due to arrive at Dûr that morning and they felt some anxiety as to its safety, since the desert was much disturbed. There are no soldiers posted on the left bank of the Tigris, and every man must protect his own property. But we, having come only from Abu Dulâf, could not reassure them. On the outskirts of Dûr the plain is once more tossed into ruin-mounds, probably of the Mohammadan period. The village stands upon an old site; Dûr is mentioned by Ammianus Marcellinus in his account of Jovian’s retreat. It is remarkable only for the shrine of the Imâm Dûr (Fig. 126), Muḥammad ibn Mûsa ibn Ja’far ibn ’Alî ibn Ḥussein--his genealogy goes back to a respectable Shî’ah ancestry, and I read it on an inscription cut upon a marble slab by the door. Moreover, while we waited for the mullah to appear with the key, one of the villagers busied himself with scraping away the whitewash which covered the lower part of the inscription, and we deciphered the date, 871 of the Hijrah, which is 1466 A.D.[124] While we were thus engaged the [Illustration: FIG. 127.--IMÂM DÛR.]