In 655, Oswiu defeated and killed Penda at the Battle of the Winwaed. Oswiu installed Peada, a son of Penda, as king of southern Mercia and ruled the northern half himself; after Peada was murdered in 656 Oswiu took direct control of all of Mercia. A coup in 658 threw off Northumbrian overlordship and established Wulfhere as king. By the early 670s, Wulfhere had become the most powerful king in southern Britain, with an effective hegemony over all the Anglo-Saxon kingdoms except for Northumbria.