Beowulf rules the Geats for fifty years. At around line 2210, the poem says that after the death of Hygelac and his son Heardred, Beowulf ruled well “for fifty winters, grew old and wise / as warden of the land.” For those fifty years, Beowulf lived an exemplary life; he behaved with honor, did not cut down a comrade who was drunk, and controlled his tremendous strength.
It is after this protracted period of prosperity that Beowulf’s final challenge, the dragon, appears. Someone has broken into the dragon’s lair and stolen a jeweled goblet, enraging the dragon. The dragon lays waste to fortifications up and down the coast, and even destroys Beowulf's own throne room. Beowulf chooses not to raise an army to fight the dragon, figuring that he and eleven companions should be able to defeat the monster.