in 672 the picts revolted and threw out the king that the northumbrians had placed on the throne there. ecgfrith sent his army into pictland (scotland) to punish them. he defeated the picts and appointed his ealdorman beornheth to rule over them. in 674 wulfhere of mercia and his allies attacked northumbria. wulfhere was trying to reclaim lindsey. but ecgfrith defeated wulfhere and made him pay tribute. wulfhere was succeeded as king of mercia by his brother aethelred in 675. ecgfrith arranged for his sister osthryth to marry aethelred. but in 679 aethelred defeated ecgfrith in battle at the river trent. to prevent a blood feud between the two royal families, theodore, the archbishop of canterbury stepped in to prevent further bloodshed. he secured a truce between northumbria and mercia that lasted for 50 years. ecgfrith next turned his attention to the britons of rheged. he drove them out of northern england and into ireland. there they became mercenaries for the irish kings and also began raiding the english coast. in 684 ecgfrith led his armies against the kingdom of brega, north of present day dublin in ireland. he won a victory and returned to northumbria. at this point he may have become too confident. in 685 ecgfrith again attacked the picts but this time he was defeated and killed. on 20 may 685 his forces were drawn into an ambush at nechtansmere near forfar in scotland. ecgfrith and his second wife eormenburg had no children. ecgfrith was succeeded by his half-brother aldfrith. queen eormenburg retired to carlisle abby.