In the reading due yesterday, we read that after Beowulf defeats Grendel and the Danes and the Geats begin to celebrate, a poet in Hrothgar's court starts to put Beowulf's heroics to verse. He begins by reciting the exploits of another hero, Sigimund, and his battle with a dragon ("wyrm" in Old English). This is an example of oral storytelling and could perhaps be the story-within-a-story hinting to how the epic of Beowulf got its start. In the times of Old English, a poet, called a "scop", would tell long, elaborate tales, entirely from memory and often with the aid of a harp. Imagine sitting around a fire, drinking mead with your friends, as local scop tells the harrowing tale of Grendel. Remember, this was a time when there was no other media by which to lose yourself, so storytelling was a very intimate and communal form of entertainment as well as education. You can imagine how popular the tale was that after a time someone skilled in writing putting down in letters and captured it forever. Had Beowulf not been written down, we might not have been able to enjoy this story.
Here's Benjamin Bagby performing the epic of Beowulf the way it would have been over a thousand years ago: