Who is Beowulf's maternal grandfather?

Beowulf’s maternal grandfather is Hrethel, the king of the Geats. Hrethel is Beowulf’s maternal grandfather because Hrethel’s unnamed daughter married Ecgtheow, who became Beowulf’s father. The poem identifies Beowulf as part of Hrethel’s family through this maternal line.

Hrethel is also the father of Hygelac, Herebeald, and Hæþcyn. Hygelac is therefore Beowulf’s maternal uncle, and Beowulf grows up closely connected to the Geatish royal household. Hrethel takes Beowulf into his care as a child, a practice known as fostering that could strengthen bonds between families and create lasting obligations.

Hrethel’s life ends in one of Beowulf’s most tragic episodes. His son Hæþcyn accidentally kills his brother Herebeald with an arrow during a hunting incident. Because the killing is accidental, it cannot be answered through ordinary blood-feud revenge. Hrethel dies from grief, leaving the Geatish succession unsettled.

Readers sometimes confuse Hrethel with Ecgtheow, Beowulf’s father, or Hygelac, Beowulf’s uncle and later king of the Geats. Hrethel is the grandfather on Beowulf’s mother’s side.