The era of Viking dominance was brought to a decisive end by several key figures across Europe, most notably King Alfred the Great of Wessex. In 878 AD, Alfred defeated the Great Heathen Army at the Battle of Edington, forcing the Viking leader Guthrum to convert to Christianity and retreat to the "Danelaw" region of eastern England. This victory laid the groundwork for the unified Kingdom of England. In Ireland, the Vikings were famously defeated at the Battle of Clontarf in 1014 by Brian Boru, the High King of Ireland, which significantly weakened their political power on the island. The final "death blow" to the Viking Age is often cited as the Battle of Stamford Bridge in 1066, where the English King Harold Godwinson defeated the Norwegian King Harald Hardrada. These defeats, combined with the gradual Christianization of Scandinavia and the rise of organized European nation-states, eventually transformed the Vikings from raiders into integrated settlers and traders.