Cyniburga (Kineburga, or Kinneburga), a Welsh saint, born in the latter part of the 7th century, was a daughter of Penda, the pagan king of Mercia, and sister of Cyneswitha (q.v.). She married Alfrid, king of Northumbria, but left him "pro amore Dei," and entered the monastery which her brothers Wulfhere and Ethelred, kings of Mercia, constructed, and which was called after her "Kineburgee Castrum " or "Castre." The two sisters were both present at the consecration of Medeshamstede, in the reign of their brother Wulfhere, and signed the charter; and it is said that in the 11th century Aelfsi, abbot of this monastery (then called Peterborough), removed their bodies from Castre, where they died, to Peterborough. The account of these sisters resembles that of Cuenburga and Cuthburga, sisters of Ina, king of Wessex. See Smith, Diet. of Christ. Biog. s.v. SEE CUENBURGA.