The Pale Horseman by Bernard Cornwell

Set in ninth-century England as Viking invasions threaten Wessex, a young warrior torn between his Saxon birth and Danish upbringing is disgraced, turns to raiding, and rescues a mystic queen whose counsel draws him back to a fugitive king in the marshes. Amid treachery, religious tension, and bitter rivalries, he helps rebuild a shattered force and marches toward a decisive battle where shieldwalls, strategy, and hard choices determine the survival of a kingdom.

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