Ironside ( cavalry ) The Ironsides were troopers in the Parliamentarian cavalry formed by English political leader Oliver Cromwell in the 17th century , during the English Civil War . The name came from " Old Ironsides " , one of Cromwell ' s nicknames . A contemporary Parliamentarian newspaper asserted that it was the Royalist Prince Rupert who had given Cromwell the nickname after Rupert ' s defeat at Marston Moor in July 1644 : " Munday we had intelligence that Lieutenant - Gen . Cromwell alias Ironside ( for that title was given him by P . Rupert after his defeate neere York ) [ i . e . , at Marston Moor ] was about Redding ( sic ) with 2500 horse marching towards Sir William Waller . " " The model regiment . Cromwell first mustered a troop of cavalry ( then referred to as " horse " ) at Huntingdon in Huntingdonshire , on 29 August 1642 , early in the Civil War . John Desborough was quartermaster . The troop was late in being organised , and arrived too late to participate in the Battle of Edgehill , the first pitched battle of the war . Cromwell however did witness the defeat of the Parliamentarian horse at the battle and wrote to fellow Parliamentarian leader John Hampden , Your troopers are most of them old decayed servingmen and tapsters ; and their [ " the Royalists ' " ] troopers are gentlemens ' sons , younger sons and persons of quality ; do you think that the spirits of such base and mean fellows [ " as ours " ] will ever be able to encounter gentlemen that have honour and courage and resolution in them ? Within the Eastern Association . It is evident that Cromwell ' s answer to his own question lay in religious conviction . Early in 1643 , he was given a commission as Colonel and expanded his troop into a full regiment in the newly formed Army of the Eastern Association , under the command of Lord Grey of Warke and then the Earl of Manchester . By 11 September that year , he referred to them in a letter to his cousin Oliver St . John as a " lovely company " . A champion of the " godly " , Cromwell became notorious for appointing men of comparatively humble origins but stoutly - held Puritan beliefs as officers , who would then attract men of similar background and leanings to the regiment . He wrote to the Earl of Manchester , who disagreed with this policy , I had rather have a plain russet - coated captain that knows what he fights for and loves what he knows , than that which you call a gentleman and is nothing else . I honour a gentleman that is so indeed . On 28 July 1643 , the regiment took part in the Battle of Gainsborough , where Royalist cavalry were defeated . One of the troop captains , James Berry , is stated to have killed the Royalist commander , Sir Charles Cavendish , a relation of the Marquess of Newcastle ( Commander - in - Chief of the Royalist forces in the North ) . The regiment ' s troops in 1643 were : By April , 1644 , after two years of war , Cromwell ' s unit had grown into a " double " regiment of no less than 14 troops . ( A regiment normally had only 6 troops ) . Cromwell by this time was Lieutenant General of the Horse in the Parliamentarian Army of the Eastern Association , and the regiment would be routinely commanded by its Lieutenant Colonel , Cromwell ' s cousin Edward Whalley . The regiment played a major part in the victory over the Royalists at the Battle of Marston Moor , where the discipline of Cromwell ' s wing of horse was decisive . Where a victorious wing of Royalist cavalry scattered in search of plunder , Cromwell ' s men rallied after defeating their immediate opponents , and then swept the disordered Royalist armies from the field . Captain Valentine Walton , Cromwell ' s nephew , died of wounds after a cannon shot smashed his leg during the battle . It was a different story by the time of the Second Battle of Newbury later that year . The Parliamentarian high command of Sir William Waller , the Earl of Manchester , Sir William Balfour and Cromwell decided to split their large force into two . Cromwell , the Eastern and London Association Cavalry and the Southern Association headed across the river and toward Donnington Castle in the West . The regiment was part of the first attack on the King ' s western forces under Goring and Astley , but was beaten back and had to be relieved by Cromwell ' s fellow commander , Sir William Balfour , and his London horse . The template for the New Model Army . Cromwell ' s double regiment was later split into two regiments ( Sir Thomas Fairfax ' s and Edward Whalley ' s ) , which became the nucleus of the New Model Army ' s cavalry . Shortly before the Battle of Naseby , Cromwell was reappointed Lieutenant General of Horse in the Army , and later became its commander . " Ironsides " seems to have become the term for all cavalry in the Army , regardless of their origin . Two " divisions " i . e . half - regiments of three troops each , one from each of Fairfax ' s and Whalley ' s regiments , under Major Christopher Bethel and Major John Desborough , mounted a remarkable charge at the Battle of Langport , where they galloped up a narrow lane and attacked the Royalist Army of Lord Goring in front , putting the entire army to flight . Dress , equipment and nature . Although the phrase " Ironside " suggests heavily armoured men , Cromwell ' s troops were equipped in the common cavalry style of the day , termed the harquebusier , with armour limited to back - and breastplate and " pot " helmet . It does seem that they presented a uniform appearance which contrasted with that of the Cavalier horse , which became increasingly individual during the war through shortage of equipment or personal choice . As Puritans , the Ironsides often attributed their glory in battle to God . Their religious beliefs extended to the field where they adhered to strict ethical codes . In quarters , they did not drink or gamble . They did not partake in the traditional spoils of war and did not rape , or pillage defeated opponents ( although their religious zeal sometimes led them to be merciless to Catholic enemies ) . In Fiction . The Ironsides are featured in Rosemary Sutcliff ' s 1953 historical fiction novel " Simon " , and are portrayed as being very professional soldiers with strong puritan religious tendencies . In Music . Lawrence J . Epstein writes that the lyric " heaven is like Ironside ' s " in Bob Dylan ' s I Pity the Poor Immigrant refers to the puritanical view of religion shared by the followers of Cromwell .