Niamh and the Viking Prince

Viking Gormlaith is married to Brian Boru and she has two sons from her previous marriage Sitric, King of the Dublin Danes and Olaf. Niamh falls in love with Olaf. He, however, becomes a Christian, then states he wishes to become a priest so he will have direct access to the sacristy, which contains a chalice ornamented with priceless jewels and which he wants to steal at his mother's behest. His mother is politically devious and wants one of her sons to become High King. Maelmorda, her brother, king of Leinster wants the High-kingship as well. Gormlaith decides to expedite Brian's death by having him poisoned. Lonan, a physician, arrives in Sitric's palace and tells Sitric he is an expert in everything to do with poisoning. He also said that because of family rivalry he hates Brian. Sitric sends him to Gormlaith but little do they realise that Lonan is in fact a friend of Brian and saves him. Foreign kings and princes were aware that Gormlaith was high queen and whoever married her would be high king.
Sitric told her I have promised you in marriage to Sigurd from the Orkneys then I promised you to Brodar, king of Denmark. Carrol Cnut and Anrud, sons of the king of Norway are looking after their father's interests and didn't come here so that the others could have Ireland between them. Obviously someone will stay back from battle and move in to annihilate the others and have Ireland for themselves. However, they were all beaten in battle by Brian but he was slain by Brodar.