Information Cromwell Museum Type of Activity Summer at the Museums In 1653, Oliver Cromwell became the most powerful person in England - the first person who was not royalty to rule. How did this happen? Find out more with these activities. Click here to download the activity pack! If you've tried any of the activities from this year's Summer with the Museums line-up, let us know what you think for your chance to win a £50 voucher from Amazon!