According to the ancient tale Culhwch ac Olwen, Mabon son of Modron was kidnapped when he was three days old and imprisoned in Gloucester Castle for many years. His rescue was one of the six impossible tasks imposed on Culhwch and his companions (knights of King Arthur's Round Table) by the giant Ysbaddaden Bencawr in order for Culhwch to win the hand of Olwen.

References

Oxford Companion to the Literature of Wales, edited by Meic Stephens. (Oxford: Oxford University Press, 1986)
The Mabinogion, trans. by Gwyn Jones and Thomas Jones. (London: Dent, 1949) (Everyman's Library)
Y Mabinogion, diweddariad gan Dafydd Ifans a Rhiannon Ifans. (Llandysul: Gwasg Gomer, 1980)

Indexes

Mythological, Traditional and Divine Figures
European
Britain
Exile or Persecution (religious, Political or Social)
Multiple or Unspecified
Birth or Infancy
Captured by Another Tribe or Group
Trans-Racial, Trans-Tribal, International or Trans-Cultural Adoption or Fostering
Temporary Care
Customary or Traditional Adoption, Informal and Extra-Legal Care
Adoptees/Fosterees from Wealthy, Famous, Noble or Divine Birth Families