Oliver Cromwell is one of the most significant figures in British history - and one of the most misinterpreted.

In this major new biography, John Morrill argues that Cromwell has been seriously misinterpreted by historians, not least by left-wing thinkers such as Tony Benn, who claim Cromwell as their own and thus misunderstand the nature of Cromwell's political thought, which was in fact a product of his religious ideas. And in this, asserts Morrill, Cromwell was entirely sincere.

With new research and insight, this exploration of his life reveals a man who never doubted that he was doing God's will - which included murdering over 3,000 people, among them Catholic clergy, after the Siege of Drogheda, ordering the religious killed on sight, and signing Charles I's execution order. Morrill also looks at the long shadow Cromwell cast over Irish history, with policies that have been accused of verging on genocide.

He sheds exciting new light on Cromwell, both political and religious, with analysis that is based on the latest scholarship of the highest quality, arguing against contemporary critics and claiming that Cromwell was a man of fundamental sincerity and devotion to high Puritan principles.