The fifth book of Xenophon's Anabasis presents a puzzle which Mr. Tarn has not discussed in his most stimulating chapter on the ‘Ten Thousand’ in the Cambridge Ancient History. Xenophon is telling the story of the retreat along the shore of the Black Sea. At Cotyora, at Xenophon's own suggestion (so he tells us) a general кαθαρμός was held by the survivors. For some time past the troops had been beginning to get badly out of hand. There had been a particularly disgraceful scene at Cerasus, which they had left a week before their arrival at Cotyora. Certain local tribes of the Colchi had sent ambassadors to the Greek army, which was actually leaving the town at the moment of their arrival. Most of the troops were already outside the walls; but some stragglers who were still within the town stoned the ambassadors to death, and a general riot ensued. Now, not a word of this story is told by Xenophon in its proper place in the narrative (V. 4, 1), where we are simply told that the Greeks left Cerasus, some by sea and seme by land. The whole story is told later in great detail, and in a curious form: as a digression which Xenophon makes in a speech immediately preceding the court of enquiry at Cotyora.