The New Model Army was the most famous of various Parliamentarian armies in the English Civil War. It was an army of professional soldiers led by trained generals, unlike other military forces of the era which tended to be led by aristocrats with no guarantee of military training. They also became famous for their Puritan religious zeal.
The New Model Army was formed from the existing Roundhead forces on February 15, 1645 onwards when Oliver Cromwell passed the Self-denying Ordinance to remove the former leadership of the Roundheads. It was led by Thomas Fairfax and at first Cromwell was only in charge of the cavalry. It finally came into being in April 1645.
The New Model Army consisted of 22,000 soldiers, including 11 regiments of cavalry (6600 men), 12 regiments of infantry (14,400 men) and 1 regiment of 1000 dragoons. Soldiers were conscripted from all over the country and older regiments were merged to join the army.
Leadership and promotions were meant to be based on proficiency instead of social standing or wealth. However, Cromwell also preferred soldiers that were devoted Puritans like himself and some of them sung psalms prior to battle. He also instituted standard daily pay (8 cents for infantry, 2 shillings for cavalry) and guarantee of food, clothing and other provisions. Cavalrymen had to supply their own horses.
Cromwell merged men from multiple regiments into a single one and provisioned them with red uniforms to replace their former regiment colors. "Soldier's catechism" dictated new regulations and drill procedures.
Prince Rupert, one of the King's followers, nicknamed them as Ironsides. However, this was more due to their ability to cut through opposing forces than their armour, as has been sometimes claimed; their armour was composed of leather jerkins.
Tactics of the New Model Army were based on fast hit-and-run attacks against the flanks of the enemy. Frontal attack would have meant exposing them to the Royalist artillery. Cromwell specifically forbade them to pursue a fleeing enemy and hold the battlefield.
The New Model Army won important victories at Naseby (when they were first used) and Preston. After the end of the civil war, they fought in Scotland, Ireland, Flanders and Spain. After the campaigns in Ireland in the 1640's some of them retired to settle in what is now Northern Ireland.
Increasingly concerned at the political manoverings by King Charles and some in Parliament, the army marched to London in August 1647 and debated proposals of their own in the Putney Debates.
In 1649 there was a mutiny over pay and political demands. Pay was sorted out, but 400 troopers under the command of Captain William Thompson who were sympathetic to the Levellers continued to negotiate their political demands. Cromwell launched a night attack on the "Banbury mutineers". Several mutineers were killed in the skirmish, but Captain Thompson escaped only to be killed in another skirmish near the Digger community at Wellingborough. Three other leaders were hanged, William Thompson's brother, Corporal Perkins and John Church on May 17, 1649. This destroyed the Leveller's power base in the New Model Army.
During the Battle of the Dunes (1658) the red-coats of the New Model Army under the leadership of Sir William Lockhart, Cromwell's ambassador at Paris, in Turenne's army astonished both the French and Spanish armies by the stubborn fierceness of their assaults particularly with a successful assault up a strongly defended sandhill 50 meters (150 feet) high. (The English had learnt a lot about war since two rabbles had met at the battle of Edgehill in 1642)