Complex sentence: In addition to being Wulfhere's godson, King Æthelwealh of the South Saxons had a connection to the Mercians via marriage: his wife was Queen Eafe, who was the daughter of Eanfrith of the Hwicce, whose territory lay to the southwest of Mercia.
Split into simpler sentences: In addition to being Wulfhere's godson, King Æthelwealh of the South Saxons had a connection to the Mercians via marriage. His wife was Queen Eafe, the daughter of Eanfrith of the Hwicce, a tribe whose territory lay to the southwest of Mercia.