Thomas Cromwell was powerful for a while in the time of Henry VIII.
Oliver Cromwell was the one who was Protector, if that is the right word, after Charles I was beheaded. I'm not sure what morals were forgotten in Oliver Cromwell's time. One thing which I learned about him about 2 years ago is that Jewish people were allowed back into England(?) during his time in power. I don't know if he could be said to have reigned. (Not rained (weather) or reined (horses)).
The book '1066 And All That' says that the Cavaliers were Wrong but Romantic and the Roundheads were Right but Rotten.