[PDF] Oliver Cromwell By Theodore Roosevelt. The year before being elected president Theodore Roosevelt wrote this history of Oliver Cromwell. It includes chapters on the times and the man, his involvement with parliament and both civil wars, the Irish and Scotch Wars, and then his time as the protectorate. It is a rare piece of history when one great leader writes about another. The insights seem more personal and the analysis more candid. This biography offers invaluable insight into the minds of two men who both led nations, but were separated by centuries.