When Hygelac died, Queen Hygd offered Beowulf to take the throne as Heardred, her son, was too young to rule the Geats. Beowulf refused but promised to serve the young king till his dying day. But Heardred was killed in a battle. Then Beowulf became the King of the Geats and protected his people for 50 years.
When Beowulf returned to his tribe, he “was formidable in battle yet behaved with honour and took no advantage.” Hygelac highly respected him. He gave Beowulf a gem-studded sword “and then rewarded him with land as well, seven thousand hides, and a hall and a throne.”
King Hygelac and his heir, Heardred, were killed in separate conflicts. The poem does not provide much detail on this point. “Hygelac fell and the shelter of Heardred’s shield proved useless against the fierce aggression of the Shylfings.” The protagonist could have become king immediately after the king’s death but was too loyal to spur his ambition. Queen Hygd was eager to make Beowulf the next king. She realized that her son did not have the necessary life experience to become the successor to the throne after her husband. Besides, Beowulf proved to be a mighty warrior in his battles with Grendel and his mother.
Beowulf declined her offer. Instead, he was a loyal protector and advisor to Heardred. But Queen Hygd was right: Heardred died in the battle with King Onelaб who wanted to revenge his father’s death. As far as Hygelac and Hygd had no more children, Beowulf ascended the throne. He ruled the Geats for 50 years until a slave disturbed the dragon.