Moninne was born around 435 in the Donaghmore area of County Down. Her father was Machta, King of the territory stretching from Louth to Armagh and her mother was Comwi or Coman daughter of one of the northern kings. It was said that she was baptised and confirmed by Saint Patrick. When he was passing through the lands of Machta he stopped at her parents' house and predicted that Moninne's name would be remembered throughout time. It was said that she was veiled by Saint Patrick also.