Not a king, but probably a powerful man in the Roman administration, Donaut was brother of Caradoc of Dumnonia and appears to have inherited his influence in the Civitas Dumnoniorum. He gave his daughter, St. Ursula, in marriage to Conan Meriadoc, but she would only consent if she was first able to go on a pilgrimage with eleven thousand virginal followers. They were all massacred in Cologne