It was by the trickery of his mother that Conor MacNessa became King of Ulster. Connor’s widowed mother Ness had no hope of a throne for him by right of his birth, but beauty she did have in abundance and she set out to seduce Fergus MacRi, king at that time. Rich and powerful though he was, Fergus could not obtain her consent to marriage despite his constant courtship. At last, when she had worn Fergus to the bone, Ness agreed on one condition—that he leave his kingship for a year, placing Conor on the throne during that time so that his issue could claim descent from the line of a king.
Now Fergus called it only a sop to her pride and was reluctant to concede this point and rightfully so. For when he finally agreed and he and Ness were wed, she lost no time in suborning the people to Conor. Rich bribes and abundant favors won them so that when Fergus went to retake his throne none would have him, saying if he had left it for a woman it could not have meant much to him.
Leaving Ness behind, Fergus and a band of followers departed for Connaught, where they were harbored at the court of Queen Maeve and her beloved, Aillil. During that time, Fergus fought alongside the men of Connaught against his own Ulstermen in the Tain Bo Cuaigne where Ulster’s champion Cuchullain met with Maeve’s army. It being impossible to prevail against the great hero, the men of Connaught were turned back and Fergus with them. And Fergus descended into deep bitterness and grief for the loss of his lands, saying that he must have sight of them again before he died.