When his father King Christopher I was murdered in 1259, Prince Eric was too young to rule in his own right. The Danish court appointed his mother, Queen Margaret Sambiria (Danish: "Sprænghest") as regent. She was the daughter of Sambor II, Duke of Pomerania and Matilda of Mecklenberg, and was a clever and intelligent woman. Immediately, she had to fight to keep her son on the throne from two powerful enemies; Archbishop Jacob Erlandsen (ca. 1220–1274) and Erik Abelsøn who was Duke of Schleswig from 1260 until his death in 1272.