before beowulf fights grendel what is the political and familial relationship between hrothgar and beowulf?

We learn that he is beloved of his people, a faithful thane of Hygelac, and a prince in his own right (through his father Ecgtheow). Hrothgar welcomes Beowulf as the son of Ecgtheow, the man whom Hrothgar had helped in settling a feud with the Wylfingas long ago. When Hrothgar did that, he was a young man and a new king.