The Last of the Vikings (1961)

Harald and younger brother Guntar return to Norway after a 10-year voyage to find their father murdered and his lands now ruled by the villainous Sveno. As part of his plan to rally the Vikings against this tyrant, Harald disguises himself as the Danish ambassador and enters Sveno's stronghold. There, he falls in love with Hilde, Sveno's cousin, who's been betrothed against her will to the Danish king. Harald must devise a new plan when Guntar is captured by Sveno and when the real Danish ambassador arrives on the scene.