Beowulf and Grendel, page 3

Explanation of the account of Beowulf versus Grendel
The adventures of Beowulf were
probably handed down from generation to generation, in the story-songs of traveling bards
 

 
Truth or fiction? The battle-description may tell us which.
 
Consider this explanation for this account: It is clear that much damage was done to the building during the fight; the record is clear on that. Grendel may have bumped his head on the ceiling (he was said to be bigger than any man), causing a shifting of a ceiling-beam. The outcome? The creature got its arm stuck where the wall joins the ceiling: Grendel twisted and tore off his own arm. (The account says that a wound appeared at Grendel's shoulder.) This explains why the actual account does not give Beowulf direct credit for tearing off the monster's arm. The man is rightfully praised and rewarded for his heroism, and why should they care about such a detail? But it is noteworthy for us, for if this were a completely fictional tale, why would it be written this way? A fiction would be for the purpose of glorifying the hero, and so the monster's appendage would end up in Beowulf’s hand, not near the ceiling, still embedded there. It seems that this is an account of an actual battle.
Beowulf and Grendel, page 4
Beowulf and Grendel, page 2
Letter from two happy parents (about child care)