The oral tradition is the way people told stories in ancient times, especially because there was no writing or it was too difficult to make because of many hindrances (costs, materials etc.).
So oral poetry was the form these stories were told, and some of the most important stories of all time were first told this way, such as Homero's books, Iliad and Odyssey.
Beowulf was, too, first told in this way – orally –, and was passed down generation after generation, until the oral tradition began to give space to the written books (books in those times needed to be hand-writed entirely, since there was no machine capable of doing that).
The first Beowulf book was written in Old English, between 975-1025. Some say that this epic poem is too good to be from the oral tradition, but this argument is easily brought down by Homero's books, whose epic poems are the pillar of the western culture and are also from the oral tradition of ancient times.
