But between these two points the Euphrates can easily be crossed in boats at many places,[15] and in the numerous Roman expeditions against the Sasanians, when Hierapolis came to be used as a convenient starting-point for eastern campaigns, the passage seems usually to have been made lower down than Birejik, more nearly opposite Hierapolis, and the Mesopotamian road ran thence by Thilaticomum and through the desert to Bathnæ in Osrhœne.[16] Julian marching from Hierapolis presumably took this shorter road, for he was anxious to reach Mesopotamia before intelligence of his movements should have come to the enemy,[17] and it has been conjectured that he threw his bridge of boats across the river from Cæciliana, a place mentioned in the Peutinger Tables and identified tentatively with Ḳal’at en Nejm.[18] There is, however, a ferry just below the mouth of the Sajûr river which during the last few years has been used regularly by caravans and carriages going to Urfah, the ancient Edessa, in preference to the longer road by Birejik. This route had long been abandoned on account of the insecurity of the deserts through which it passes. Before the granting of the constitution some advance had been made towards order, and since the overthrow of Ibrahîm Pasha, the Kurd, in the autumn of 1908, it has become as safe as can reasonably be expected. The landing-place on the east bank is at Tell Aḥmar, a tiny hamlet which has inherited the site of a very ancient city. Here perhaps Strabo’s road crossed the river;[19] here Julian may have constructed his pontoon bridge, and it is not improbable that for the first four or five hundred years of the Christian era it was the customary point of passage for travellers from Hierapolis to Edessa.[20] Thapsacus, which lies lower down than Cæciliana-Ḳal’at en Nejm, was of earlier importance. Xenophon crossed there, and nearly a hundred years later, Darius, fleeing headlong eastwards with his broken army after the battle of Issus, with Alexander headlong at his heels, passed over the river at Thapsacus.[21]