After some time Nessa left her husband, taking her son with her. It may be that she had discovered he was the murderer of her tutors. It may have been that she did not love him; it may even be that she did not like being wife to a magician, or he may have grown tired of her. But she never returned to him again.
But when Conachúr was a youth Nessa was still the most beautiful woman of Ulster. The then King of Ulster, Fachtna the Mighty, died, and his young half-brother, Fergus, the son of Roy, wife of Ross the Red, son of Rury, came to the throne. Fergus was then eighteen years of age and Conachúr was sixteen, and, like Conachúr, Fergus also was known by his mother’s name instead of his father’s.
Nessa came to the Ulster court with her son, and while there Fergus fell madly in love with her, and she could in no way avoid the importunities of that monstrous youth, for Fergus was gigantic in bulk and stature.
“I shall marry you on one condition,” said Nessa.
“I agree to it beforehand,” said Fergus.
“You know the great love I bear my son, Conachúr?”
“I also love him,” said Fergus.
“His descent is kingly,” she said, “and I desire that he should be a king if it were only for a year. If you resign the crown to him during our first year of marriage I will marry you.”
“I will do that,” said Fergus.
That was done, and for a year Fergus and Nessa lived happily together.