The ECW for beginners...
The Civil War was one of those interesting times the Chinese had curses about. In 1625 the monarchy had fallen into the hands of an utter pillock, King Charles I, who tried to rule his three kingdoms (and one principality) of Scotland, Ireland and England (and Wales), without calling any parliaments. He managed it for a few years by taking a few liberties with the tax system he probably shouldn't have, but eventually people started to grumble.
The Scots rebelled first, ostensibly over a prayer book, but it soon got political. Charles botched the campaign to put them down, which encouraged the Irish to rebel as well, and he had to call a parliament in England to ask for more tax money and more troops. They wouldn't give him any without some concessions and reforms, arguing the toss with their divinely appointed monarch with gusto. Charles wouldn't compromise and told them all to bugger off home, they refused. Parliament started calling up the militia while the King revived the feudal levy, and it all went downhill from there.
The British Isles had missed out on the carnage of the Thirty Years War, but made up for it now with a religious/political war that saw the usually phlegmatic Brits get just as fanatical and rabid as anyone on the continent. It was described at the time as 'the world turned upside down', and as the war went on more and more eccentric religious cults and political movements emerged. Lots of people thought in millennialist terms, and this mundane scrap over taxation and representation became the prelude to the Apocalypse itself with Charles and/or Cromwell cast as the Antichrist depending on whose propaganda you read.
All ripe for a a fantasy RPG really, just turn the loopiness of the time up a notch, have a few of the madder rumours and conspiracies real rather than imagined, make the then popular alchemy and astrology real and allow the preachers a bit of real fire and brimstone to call down and off you go.
It is going to take a bit of work though, the DCC magic system does not lend itself to quick adaptation what with all the spell tables, corruption tables, divine disfavour and so on. As key elements are finished I will post them here, and then put out a call for victims for an introductory funnel adventure.