One day, when he had come from his own Dun to the yearly Assembly in the great Hall of Tara, he ate not at the banquet but gazed as it were at something afar off, and his wife said to him, "Why dost thou gaze so, Ailill; so do men look who are smitten with love ?" Ailill was wroth with himself and turned his eyes away, but he said nothing, for that on which he gazed was the face of Etain.
After that Assembly was over Ailill knew that the torment of love had seized him for his brother's wife, and he was sorely shamed and wrathful, and the secret strife in his mind between his honour and the fierce and pitiless love that possessed him brought him into a sore sickness.

And he went home to his Dun in Tethba and there lay ill for a year.

Then Eochy the King went to see him, and came near him and laid his hand on his breast, and Ailill heaved a bitter sigh.

Eochy asked, "Why art thou not better of this sickness, how goes it with thee now ?" "By my word," said Ailill, "no better, but worse each day and night." "What ails thee, then ?" asked Eochy.

Ailill said, "Verily, I know not." Then Eochy bade summon his chief physician, who might discover the cause of his brother's malady, for Ailill was wasting to death.
So Fachtna the chief physician came and he laid his hand upon Ailill, and Ailill sighed.