I have an ongoing obsession with the English civil war and its fallout. It's a fascinating and crucial piece of history that is strangely under-represented in fiction – luckily, there are some decent works out there if you’re willing to dig/go on AbeBooks.
David Caute’s 1961 novel Comrade Jacob focuses on Gerard Winstanley and the mystical proto-communist sect he founded in the years after the fall of the monarchy. His ecstatic religious epiphany on St George’s Hill, Surrey, leads to the creation of the Diggers (many of them ex-soldiers from Cromwell’s army), who take it upon themselves to live collectively and farm the commons on the hill, in a time of great famine, poverty and social unrest.
It's wonderful novel about a tricky subject, exploring religious faith, power, the system of land ownership in England, and how, inevitably, brute force is meted out to those who try and live a different kind of life. (St George’s Hill, incidentally, is now home to stockbroker-belt residences and a private golf course.)