Complex sentence: In May 878 he led a force that defeated the Danes at Edington, the victory was so complete that the Danish leader, Guthrum, was forced to accept Christian baptism and withdraw from Mercia.
Split into simpler sentences: In May 878 he led a force that defeated the Danes at Edington. The victory was so complete that the Danish leader, Guthrum, was forced to accept Christian baptism and withdraw from Mercia.