Olaf II of Denmark (December 1370 – 3 August 1387) was King of Denmark as Olaf II (though occasionally referred to as Olaf III) from 1376 and King of Norway as Olav IV from 1380 until his death. Olaf was the son of Queen Margaret I of Denmark and King Haakon VI of Norway, and grandson of kings Magnus IV of Sweden and Valdemar IV of Denmark.
Olav V (Norwegian: Olav den femte, Norwegian pronunciation: [ˈûːlɑːv dɛn ˈfɛ̂mtə]; born Prince Alexander of Denmark; 2 July 1903 – 17 January 1991) was King of Norway from 1957 until his death in 1991.
Olav was born at Sandringham House in England, the only child of Prince Carl of Denmark and Princess Maud of Wales. He became heir apparent to the Norwegian throne when his father was elected King Haakon VII of Norway in 1905. He was the first heir to the Norwegian throne to be brought up in Norway since Olav IV in the 14th century, and his parents made sure that he was given as Norwegian an upbringing as possible. In preparation for his future role, he attended both civilian and military schools. In 1929, he married his first cousin, Princess Märtha of Sweden. During World War II, his leadership was much appreciated, and he was appointed Norwegian Chief of Defence in 1944. Olav became king following the death of his father in 1957.