the city was complete, and had gone to gather an army in Wessex, the traditional heartland of the English monarchy. Part of the Danish army besieged London, constructing dikes on the northern and southern flanks and a channel dug across the banks of the Thames to the south of the city, enabling their longships to cut off communications up-river. There was a battle fought at Penselwood in Somerset – with a hill in Selwood Forest as the likely location – and a subsequent battle at Sherston, in Wiltshire, which was fought over two days but left neither side victorious. Edmund was able to temporarily relieve London, driving the enemy away and defeating them after crossing the Thames at Brentford. Suffering heavy losses, he withdrew to Wessex to gather fresh troops, and the Danes again brought London under siege, but after another unsuccessful assault they withdrew into Kent under attack by the English, with a battle fought at Otford. At this point Eadric Streona went over to King Edmund, and Cnut set sail northwards across the Thames estuary to Essex, and went from the landing of the ships up the River Orwell to ravage Mercia. London captured by treaty On 18 October 1016, the Danes were engaged by Edmund's army as they retired towards their ships, leading to the Battle of Assandun, fought at either Ashingdon, in south-east, or Ashdon, in north-west Essex. In the ensuing struggle, Eadric Streona, whose return to the English side had perhaps only been a ruse, withdrew his forces from the fray, bringing about a decisive English defeat. Edmund fled westwards, and Cnut pursued him into Gloucestershire, with another battle probably fought near the Forest of Dean, for Edmund had an alliance with some of the Welsh. On an island near Deerhurst, Cnut and Edmund, who had been wounded, met to negotiate terms of peace. It was agreed that all of England north of the Thames was to be the domain of the Danish prince, while all to the south was kept by the English king, along with London. Accession to the reign of the entire realm was set to pass to Cnut upon Edmund's death. Edmund died on 30 November, within weeks of the arrangement. Some sources claim Edmund was murdered, although the circumstances of his death are unknown. The West Saxons now accepted Cnut as king of all of England, and he was crowned