In beowulf, who is seigmond?

Question

In beowulf, who is seigmond?

Answer 1

In this case, this is an allusion to the Norse legends of Sigemund (spelling varies).  He is famous for killing the dragon, Fafnir.  While Sigemund is not a character in the story, mentioning him serves to foreshadow Beowulf's own battle with a dragon.  

Answer 2

Are you spelling the name correctly?

In Norse mythology, Sigmund is a hero whose story is told in the Volsunga saga. He and his sister, Signy, are the children of Volsung and his wife Ljod. Sigmund is best known as the father of Sigurd the dragon-slayer, though Sigurd's tale has almost no connections to the Volsung tales.

When king Hroðgar, his wife Wealhþeow, and his court were terrorized by the monstrous Grendel, Beowulf left Geatland (West Götaland) and sailed to Zealand with fourteen warriors in order to pay his father's debt. During the night, Grendel arrived to attack the sleeping men. Beowulf attacked him without his sword and tore the arm off the beast. Grendel returned to the bog to die and his arm was attached to the wall of Heorot. The next day, Beowulf was lauded and a skald (scop) sang and compared Beowulf with the hero Sigmund.