Fiachu Muillethan

King of Munster. Fiachu was the son of Eógan, king of Munster, and of Moncha, daughter of the blind druid Dil Maccu Crecga of Osraige.

Dil Maccu Crecga advised Eógan to sleep with his daughter Moncha, because the druid knew that the king would die the next morning at the battle of Maige Mucrama, against the Alban forces of Lugaid Mac Con. A son was conceived to Eógan that night.

Nine months later, Moncha went into labour, but her father had foretold that if the son were born that day, he would become the chief jester of Ireland. If the child were born the next day, he would become king of Munster and would found a new dynasty, the Eóganacht.

Moncha stubbornly sat on a rock for a whole day and night, delaying the birth of her son. As foretold, Fiachu was born the next day, but he was named Fiachu of the flat head, Fiachu Muillethan. The delay was costly because Moncha died after she gave birth, so Fiachu was an orphan.

Cormac, son of Art Óenfher, was also conceived on the same night that Fiachu was. Art and Eógan were both allies against Lugaid Mac Con, but they both died in battle.

When Cormac Mac Airt was driven from Tara by Fiachu Araide, Fiachu Muillethan was Cormac's ally, and helped restore his kinsman to the throne of high king. However, they became enemies later when Cormac invaded Munster.