Answer:
The king Hrothgar called upon Beowulf help in his quest to rid Heorot hall of evil Grendel
Step-by-step explanation:
The king Hrothgar built a great place called Herot, then when Grendel who is the descendant of Cain's monsters get in a very sneaky way, and smash 30 men and run away with their bodies, Beowulf alongside his army attend to help the man and his people, this is what produces the battle between Beowulf and Grendel.