Boann

Boann was the wife of Nechtan or Echmar, who was the god of river. Boann was also the goddess of river, particularly the river Boynne. Boann was also sometimes called Eithne.

Boann had an affair with Dagda (usually referred to as Eochaid Ollathair) during her husband's absence. Dagda had her husband on a mission. Elcmar thought the journey took only one day and one night, when actually nine months passed, because Dagda used his power to hide Boann's adultery and pregnacy from Elcmar. By Dagda, Boann became the mother of Angus Óg (and possibly of Brigit). Elcmar unknowingly became the foster father of Boann's son.

According to Aislinge Óenguso (Dream of Angus), Boann was actually seen as Dagda's wife.