Carlyle's correspondence reveals that, by the time Chapman and Hall published his two volume critical edition of Oliver Cromwell's Letters and Speeches; with Elucidations in 1845, he had been considering some sort of treatment of the Civil War period for over 20 years. At various times, he had mentioned as potential vehicles for his efforts, a history of the Scottish Covenanters, a stage drama based upon the deeds of the Scottish Cavalier leader, Montrose, a biography of John Knox, and even a twelve-act tragedy about Cromwell's tumultuous life of struggle. It was as if he had something specific and important to say, but was uncertain about which historical subject and which historical form could best express his as yet …
Uglow, Nathan. "Oliver Cromwell's Letters and Speeches; with Elucidations". The Literary Encyclopedia. First published 21 March 2002; last revised 30 November -1.
[http://www.litencyc.com/php/sworks.php?rec=true&UID=3103, accessed 21 April 2015.]