Eric V of Denmark

Eric V Klipping (1249 – 22 November 1286) was King of Denmark from 1259 to 1286. After his father Christopher I died, his mother Margaret Sambiria ruled Denmark in his name until 1266, proving to be a competent regent. Between 1261 and 1262, the young King Eric was a prisoner in Holstein following a military defeat. Afterwards, he lived in Brandenburg, where he was initially held captive by John I, Margrave of Brandenburg (c. 1213–1266). During his reign, he enforced his power successfully over the church but failed to do so on the nobility, he offended the nobles and was thereby forced to accept a charter (Håndfæstning) which limited his authority while confirming the rights of the nobles.

Source: Wikipedia — https://en.wikipedia.org/wiki/Eric_V_of_Denmark