Then said the men of Erin to Tamon the fool that he should don the garments of Ailill and the king's golden shawl, and go to the ford under their eyes. So he put the garments and golden shawl of Ailill upon him [and he went on to the ford under their eyes.] The men of Erin began to scoff and to shout and jeer at him. "It is a disguising of Tamon ('Stump') for thee, O Tamon the fool" they cried, "with the dress and the golden shawl of Ailill upon thee!"

When Cuchulain saw him, it seemed to him in his ignorance and lack of knowledge that it was Ailill himself that was there. And he slung a stone from his staff-sling at him so that Tamon the fool was smitten lifeless where he was on the ford. Hence Ath Tamuin ('the Ford of a Stump') is the name of that ford ever since and 'the Disguising of Tamon' is the name of the tale.