Complex sentence: He became king of Denmark only five years old and when he later also suceeded his harther as king of Norway, and for the next more than 500 years Norway would be ruled from Denmar, until its independence in 1814.
Split into simpler sentences: He became king of Denmark only five years old and when he later also succeeded his father as king of Norway. For the next more than 500 years Norway would be ruled from Denmark, until its independence in 1814.