Oliver Cromwell remains as controversial today as he was during his own lifetime. He emerged from fenland obscurity to become Lord Protector of a united republic of England, Scotland and Ireland: he was (with the brief exception of his son Richard) the only republican head of state in British history. Plentiful sources survive that shed light on his life and career, including extensive records of his own letters and speeches. Yet much about his beliefs and motives is still the subject of debate, and the nature of his historical achievement and legacy continues to inspire sharply divided opinions.