A text compiled in Constantinople in the middle of the tenth century and based on information gathered by Byzantine agents, records the treacherous conditions that had to be negotiated on the voyage south. A set of rapids on the Dniester was particularly perilous: a narrow barrage had a lethal set of rocks in the middle of it, “which stand out like islands. Against these, then, comes the water and wells up and dashes down over the other side, with a mighty and terrific din.” This obstacle had been nicknamed with dry humour “Do Not Fall Asleep.”58
