What do we know about Beowulf and his character from when he is first introduced to the time when he proved Unferth wrong.

Beowulf points out that Unferth's fame lies mainly in the fact that he killed his own brothers. If the Dane could fight as well as he talks, says Beowulf, King Hrothgar might not have such a problem with Grendel. When Beowulf arrives at Heorot Hall, Unferth challenges him by telling the story of a swimming contest that Beowulf once lost to a man named Breka. However, Beowulf says that he only lost because he had to fight nine sea monsters after five days in icy water.