Ecgþeow was a warrior in Beowulf in the service of the Geats. In the epic we only learn that he belonged to a probably Swedish family (an ätt, see Norse clans) called the Waegmundings and that he had slain Heaðolaf, a man from another family called the Wulfings (probably the rulers of the East Geats). One of the Germanic ways of solving such an event was either to pay the wergild or to be banished. Apparently, Ecgþeow could not pay the wergild because he had to leave and go to Hroðgar, the Danish king. Hroðgar payed the wergild and had Ecgþeow swear an oath to him. Ecgþeow later married the daughter of the Geatish king, Hreðel, and had the son Beowulf.
When Beowulf arrived at Heorot, Hrothgar interprets this as a son's gratitude for what Hroðgar had done to Beowulf's father, and allows Beowulf to fight against Grendel.
Wiglaf and his father Weohstan were relatives of Ecgþeow.
Beowulf introduces himself as the son of Ecgtheow and comrade of Hygelac, and says that they have come in the hope of ridding the “old King” of the evil of Grendel.
Ecgtheow had defeated Heathloaf of the Wyfling line but had been unable to pay his family wergild, and thus the Geats refused to shelter him for fear of reprisal.
Hrothgar had then come to EcgtheowÂ’s aid and paid wergild to HeathloafÂ’s family, and Ecgtheow had sworn an oath of friendship in payment for this generosity.