Swipdag was a legendary King of Sweden and Norway. He battled against King Gram, who was the father of the (later) King Hadding. After he established the Kingdom of Norway, he reconquered the Kingdom of Sweden and defeated the Danes. This essentially made him the ruler of the larger part of Scandinavia, which is a legendary feat in itself.
He is best known for his appearance in the saga of King Hadding, by whom he is slain in the end. This makes his death as legendary as his life. Other stories tell about him saving a beautiful maiden from the grasp of some giants and meeting with Odin.