Beowulf is an Anglo-Saxon epic poem written by unknown author between about 8th and 11th century.The actions takes place in Scandinavia, but it's probably the poem was written in Northumbria by Roman Catholic monks who reinterpreted it in a Christian way.
This was sung by scoops as a entertainment. It tells about the warrior society in which the relationship between the leader, or king, and his warriors, called thanes, is founded on provision and service. In fact, the story tells about this struggle between this tribes of warrior.
The first actions take place in Danish kingdom, precisally in Herot, where there was the monster Grendel that was destroying the country. So, in the mead hall of the king Hrothgar, Beowulf killed the monster, who is a descendant of Cain. Later Beowulf dives into a lake and fights the Grendel mother's. She's like a woman and the poison in her blood dissolves any sword.
Fifty years later Beowulf killed a dragon that was terrorizing the lands of the Geats, in Sweden. The monster is a winged , fire-breathing, serpentine dragon.
The life is a continuous struggle between goodness and evil. In fact were important the courtly ideal such as courage, endurance and generosity and the own noble ancestry. So, the primary value is loyalty to one's lord or neighbor and it's also important how and when you died.
The poem deals with legends and real historical events. In fact in Scandinavia have found a hall built at the time of Beowulf and then in England, at Sutton Hoo, there are weapons and artifacts described in the poem.