Though, as has been said, there was hardly a spot in England where both parties had not adherents, yet roughly speaking a line drawn from Hull to Weymouth would divide England into a larger royalist half, and a smaller parliamentarian half, as things were just after the war had begun. The Parliament had its headquarters in London: the eastern counties, using that term very widely, were strongly on its side: and though the royalists were fairly numerous in Kent, Surrey and Hants, yet they were there so far overmatched by their opponents that the authority of Parliament was recognised. The king, whose headquarters after the first movements of the war were fixed in Oxford, was preponderant in the north (except Lancashire), in Wales (except Pembrokeshire) and the border counties, and in Cornwall, while the other south-western counties were more equally divided.
Charles I. finally set up his standard at Nottingham late in August 1642, whence he moved westwards to Chester, and when he had gathered sufficient forces marched on London. The earl of Essex, commanding the parliamentary army, had gone to Worcester to meet the king, and the first skirmish of the war took place at Powick bridge, just south of that city, on the very ground where nine years later was fought the last battle, the "crowning mercy" as Cromwell called it, which extinguished Charles II.'s last hopes of being restored by the aid of the Scots. It is a proof of the real inexperience of both sides that Charles and Essex moved towards London a few miles apart without either apparently being fully aware what the other was doing. On October 23 the king, who had the start, but had now come into hostile country, and therefore could not advance safely without beating off Essex, turned and fought at Edgehill on the southern edge of Warwickshire. The battle still further illustrated the rawness of both armies. The royalists gave away an advantage by coming down a fairly steep slope to meet their assailants: prince Rupert with the main body of their cavalry, after defeating the parliamentary horse opposed to him, pursued them headlong far away from the field, and then took to plundering Essex's baggage. The smaller body on the other wing were even more reckless, for they drove off only part of the cavalry opposed to them, leaving two small regiments untouched, in one of which was Cromwell's troop. How far this was due to want of discipline among the men, how far to lack of judgment in their commanders, it is difficult to tell; but the result was most disastrous to the king's cause. The infantry on both sides fought bravely, but two or three of Essex's regiments had been broken by the flying horsemen, and the king would have won a considerable victory but for the vigorous and effective way in which the few hundred cavalry that had escaped attack co-operated with the infantry. The clumsy, ill-made, slow-firing muskets of the seventeenth century were not very formidable to cavalry, and a charge pressed home in earnest had a very good chance against a mixed body of musketeers and pikemen, unless the latter were fresh and in good order. When prince Rupert at length returned to the field, Essex's infantry had got on the whole the best of it, though the royalists were hardly defeated: it was too late to begin again, and the battle remained drawn. The king's one chance of finishing the war at a blow was lost.