Eomer (Old English: Ēomǣr), also spelt Eomær, was (according to the Anglo-Saxon Chronicle) the great-great-grandfather of Creoda, the first King of Mercia. He is considered the ancestor to the Kings of Mercia. Eomer himself was the son of Angeltheow. Eomer's son was Icel.
He is mentioned in lines 1958-1963 of the Anglo-Saxon epic Beowulf as the son of Offa of Angel and grandson of Garmund.
...forþam Offa wæs
geofum and guðum gar-cene man,
wide geweorðod; wisdome heold
eðel sinne, þonon Eomær woc
hæleðum to helpe, Heminges mæg,
nefa Garmundes, niða cræftig. ...Hence Offa was praised
for his fighting and feeing by far-off men,
the spear-bold warrior; wisely he ruled
over his empire. Eomer woke to him,
help of heroes, Hemming's kinsman,
Grandson of Garmund, grim in war.(Gummere's translation)