God's Fury, England's Fire_ A New History of the English Civil Wars - Michael J. Braddick [199]
For those interested in contingencies then, the moment at which Charles drafted that clause, or the moment when Rupert read it, was crucial to the course of the war in England. With York relieved, the King in what turned out to be a successful pursuit of Essex, and Oxford secure, honours might have been said to be even. But Rupert chose to engage numerically superior forces, with catastrophic results for the royalist cause.
Battle was joined at Marston Moor on 2 July. Rupert’s forces were considerably outnumbered, particularly the cavalry. His relieving army and the force garrisoning York numbered about 18,000. The parliamentarians, by contrast, probably had around 28,000 men, the result of the confluence of forces under the command of Leven, Sir Thomas Fairfax and Manchester. The bulk of the parliamentary forces, about 16,000, were Scottish and Leven was in overall command both as the ranking officer and as a man of formidable experience in the European wars. His forces were drawn up with the infantry in the centre, cavalry on the right under Fairfax and on the left under Cromwell and Leslie. Opposite Cromwell were Rupert’s cavalry, commanded by Byron, and Fairfax was opposed by Goring. Infantry numbers were fairly equal – around 11,000 on either side – but the parliamentary advantage in horse was considerable. This was not a guarantee of success, however, because the ground on which the battle was fought did not favour horse riders – furze, gorse, ditches and rabbit holes broke up the ground, making rapid advances difficult. Byron, in particular, was protected by rough ground.18
The initial deployment was not complete until late afternoon, and several hours of inconclusive skirmishing had achieved little by 7 p.m. At that point Rupert thought the battle would be postponed until the next day, and Newcastle was repairing to his coach to enjoy a pipe of tobacco. But as a thunderstorm broke, the parliamentary infantry began to advance. The rain interfered with the matchlocks of the royalist advance guard and the parliamentarians” infantry successfully engaged with the main body of the royalist infantry. But the royalist riposte was very successful. Goring advanced on the parliamentary cavalry ranged against him, and his men began to inflict heavy losses. Byron, perhaps encouraged by the sight, advanced on Cromwell, but in doing so had to tackle the difficult ground himself. Perhaps that contributed to the ensuing rout, in which Cromwell’s cavalry were triumphant. But with Fairfax’s cavalry now defeated and Goring’s men inflicting heavy losses on the infantry it seemed as if Rupert’s decision might be vindicated. Many Scottish troops fled and at one stage all three parliamentarian generals appeared to be in flight, thinking that a royalist victory was in the offing.
It was the discipline of Cromwell’s cavalry that transformed this position.