The entry of the Scots into the English Civil War on 19 January 1644 on the side of Parliament radically changed the balance of power in the North of England. The Royalists in the North were forced onto the defensive and besieged in York. In a bold march Prince Rupert outmanoeuvred his enemies and relieved York without a shot being fired. However, when Rupert met the allied army in battle on Marston Moor on 2 July his cavalry was defeated by Cromwell's Ironsides who then turned on the Royalist infantry. The result was a hard-fought but catastrophic defeat; the Royalist army was crushed and their forces driven from the north of England.

Many types of cavalryman are established in the imagination of the British public, but the Ironside retains his place as symbolic of the one occasion when the army took an active role in British politics. One reason is that he represents a unique period when ordinary people displaced the established order to take political control into their own hands. In the 19th century a rash of historical publications, paintings and statues with a civil war theme reflected the political divisions of Victorian society and Royalist and Parliamentarian causes were argued over again, reflecting the subtext of contemporary political struggles. This book attempts to take a wider view of the Ironside as a warrior who evolved from the experiments of the 16th and early 17th centuries to combine firepower with the armoured cavalryman. It reflects his wider service in the Royalist as well as the Parliamentarian armies and beyond the civil wars.