In the days of long ago and the times that have disappeared for ever, there was one Fiachna Finn the son of Baltan, the son of Murchertach, the son of Muredach, the son of Eogan, the son of Neill. He went from his own country when he was young, for he wished to see the land of Lochlann, and he knew that he would be welcomed by the king of that country, for Fiachna's father and Eolgarg's father had done deeds in common and were obliged to each other.
He was welcomed, and he stayed at the Court of Lochlann in great ease and in the midst of pleasures.
It then happened that Eolgarg Mor fell sick and the doctors could not cure him. They sent for other doctors, but they could not cure him, nor could any one say what he was suffering from, beyond that he was wasting visibly before their eyes, and would certainly become a shadow and disappear in air unless he was healed and fattened and made visible.
They sent for more distant doctors, and then for others more distant still, and at last they found a man who claimed that he could make a cure if the king were supplied with the medicine which he would order.
"What medicine is that?" said they all.
"This is the medicine," said the doctor. "Find a perfectly white cow with red ears, and boil it down in the lump, and if the king drinks that rendering he will recover."
Before he had well said it messengers were going from the palace in all directions looking for such a cow. They found lots of cows which were nearly like what they wanted, but it was only by chance they came on the cow which would do the work, and that beast belonged to the most notorious and malicious and cantankerous female in Lochlann, the Black Hag. Now the Black Hag was not only those things that have been said; she was also whiskered and warty and one-eyed and obstreperous, and she was notorious and ill-favoured in many other ways also.
They offered her a cow in the place of her own cow, but she refused to give it. Then they offered a cow for each leg of her cow, but she would not accept that offer unless Fiachna went bail for the payment. He agreed to do so, and they drove the beast away.
On the return journey he was met by messengers who brought news from Ireland. They said that the King of Ulster was dead, and that he, Fiachna Finn, had been elected king in the dead king's place. He at once took ship for Ireland, and found that all he had been told was true, and he took up the government of Ulster.