In 865, several of the Danish commanders combined their respective forces into one large army and landed in England. Over the following years, what became known as the Great Heathen Army overwhelmed the kingdoms of Northumbria and East Anglia. Then in 871, the Great Summer Army arrived from Scandinavia, to reinforce the Great Heathen Army. The reinforced army invaded Wessex and, although Æthelred and Alfred won some victories and succeeded in preventing the conquest of their kingdom, a number of defeats and heavy losses of men compelled Alfred to pay the Danes to leave Wessex. The Danes spent the next few years subduing Mercia and some of them settled in Northumbria, but the rest returned to Wessex in 876. Alfred responded effectively and was able with little fighting to bring about their withdrawal in 877. A portion of the Danish army settled in Mercia, but at the beginning of 878 the remaining Danes mounted a winter invasion of Wessex, taking Alfred by surprise and overrunning much of the kingdom. Alfred was reduced to taking refuge with a small band of followers in the marshes of the Somerset Levels, but after a few months he was able to gather an army and defeated the Danes at the Battle of Edington, bringing about their final withdrawal from Wessex to settle in East Anglia. Simultaneous Danish raids on the north coast of France and Brittany occurred in the 870s – prior to the establishment of Normandy in 911 – and recorded Danish alliances with both Bretons and Cornish may have resulted in the suppression of Cornish autonomy with the death by drowning of King Donyarth in 875 as recorded by the Annales Cambriae. No subsequent 'Kings' of Cornwall are recorded after this time, but Asser records Cornwall as a separate kingdom from Wessex in the 890s.