Viking invasion of Britain
In 872 the Northumbrians rebelled against the Danes and ejected King Ecgberht. They placed King Ricsige on the throne. Ecgberht took refuge in Mercia. The Danes came north to put down the rebellion, but succeeded only in subduing Deira. Within a few weeks the Danes set up their winter camp at Torksey in Mercia. The Danes had operated as a single army for nine years. But in 874 it divided into two armies. They never reunited.