On this day in 1643, Cromwell won the battle of Gainsborough. The English Civil War had begun the year before. Charles I had fled London with his family to Hull in Yorkshire, but being ejected from there, had set up in Nottinghamshire. The Rollestons of Nottinghamshire, who had in earlier times held royal office, now as simple squires raised a regiment in support of the king. This Frances Rolleston remembered as part of her family history.
Not all gentry supported the king, and not all commoners supported the war against the king. The situation was far too complicated for that. It included matters of religious freedom (especially concerning the Scottish Presbyterians and Charles I's efforts to formalize the Anglican liturgy) and political freedom (Scotland, Ireland and England were all involved) and the organization of the English government (changes to limit the king's power).
Two hundred years after the English Civil War had passed into history, Frances found it interesting enough to read about—for fun. This from a letter of 1856:
"For relaxation I am deeply engrossed, in my usual fashion, with two books at once, Carlyle's and Merls D'Aubigné's 'Cromwell,' one mad first-rate, the other pious, calm, second-ratism."
Here's a link to the Wikipedia article on the English Civil War.