Battle of the Conwy In 877 they partitioned Mercia, taking the east for themselves and leaving the west to Ceolwulf. Gwynedd was also under attack from the Vikings, and in 877 King Rhodri Mawr was defeated and driven out. He returned the following year, but immediately came under attack from Mercia, which was still trying to maintain its hegemony in Wales. King Alfred's victory over the Vikings at the Battle of Edington in May 878 relieved the pressure on Mercia, and in the same year Mercia defeated and killed Rhodri Mawr. Ceolwulf died or was deposed in 879, and he was succeeded as Lord
Danelaw losses. The Danes pursued, and on 7 January 871, Æthelred and Alfred defeated the Danes at the Battle of Ashdown. The Danes retreated to Basing (in Hampshire), where Æthelred attacked and was, in turn, defeated. Ivar was able to follow up this victory with another in March at Meretum (now Marton, Wiltshire). On 23 April 871, King Æthelred died and Alfred succeeded him as King of Wessex. His army was weak and he was forced to pay tribute to Ivar in order to make peace with the Danes. During this peace, the Danes turned to the north and attacked Mercia,