The kingdom established by Alfred the Great in England is Wessex. Alfred, who ruled from 871 to 899, successfully defended his kingdom against Viking invasions and is often credited with laying the foundations for what would eventually become a unified England. He implemented significant military reforms, promoted education, and was instrumental in the establishment of a legal system. Alfred's successful efforts against the Danes had a profound impact on the political landscape of England, leading to the eventual emergence of a unified English kingdom.