Beowulf was a legendary hero of Geatland (part of Sweden), who was a loyal servant of the Geatish king, Hrodgar. The court soon got terrorized by a hostile Grendel of Zealand. Zealand and Geatland fought a war, in which Grendel and his mother was killed.
Beowulf then became the Geatish king when he removed his usurper uncle and his armies from the way. He reigned for roughly 50 years. Beowulf eventually died when he chased a dragon to its lair and got mortally wounded by the dragon's horn.