The third son of Frederick V, elector Palatine and his wife Elizabeth, the sister of Charles I, and thus a nephew of Charles I, perhaps the best known Royalist general of the Civil War. His reputation was made as a dashing commander of cavalry, but his record in command of major battles was poor. He was popular with the rank and file of the Royalist armies, but made enemies of almost every other senior commander. After the restoration he returned to England, where he had a second career as an Admiral.
Despite his youth (only 23 at the outbreak of war), Rupert was already an experienced soldier, having served under the prince of Orange in 1635, and been present at the siege of Breda in 1637. The following year he was captured during an invasion of Westphalia, and was only released in 1641.
In August 1642 Rupert landed in England, with his brother Prince Maurice, and a small group of experienced soldiers, determined to help his uncle. He joined Charles at Nottingham, from where the Royal army soon departed for Shrewsbury to collect reinforcements. Hearing that Essex was moving to threaten Worcester, Charles sent Rupert to stiffen the defence of the town if possible. Rupert soon realised that it was not, and ordered a withdrawal, which he covered from the south west of the city, where he fought the first battle of the war, at Powick Bridge (23 September 1642), a small battle, with only 1,000 men on each side, which Rupert won with a cavalry charge, much enhancing his own reputation on both sides. Back with the King, it was Rupert's scouts who discovered the Parliamentary forces before the battle of Edgehill (23 October 1642). In the battle itself, Rupert commanded the cavalry of the right wing. Early in the battle, the Royalist cavalry charged, driving the Parliamentary cavalry from the field. Rupert is often blamed for allowing the pursuit to get out of hand, but this is unfair. Only Cromwell was ever able to reliably prevent such a chase, while at Edgehill it was not just his cavalry which left the field - the same happened on the left wing under Wilmot, while most blame should perhaps fall on Sir John Byron, commanding the second line of Rupert's wing, who despite seeing that the Parliamentary cavalry had broken, still joined the chase. Rupert was eventually able to return to the field with three troops of cavalry, but by the time he was able to return to the battlefield, it was close to dark, and the battle was effectively over.
Rupert remained active over the following winter. On 2 February 1643 he captured Cirencester, as part of a general Royalist move to improve the situation around Oxford. On a sally into the midlands, he captured Birmingham (3 April) and Lichfield (21 April), improving Royalist communications with Yorkshire, before returning to Oxford. In June he launched a raid from Oxford, with just under 2,000 men, aimed at capturing a convoy carrying £21,000 of pay for Essex's army. The convoy escaped, but in a battle at Chalgrove Field (18 June 1643), John Hampton, one of the leading lights of the Parliamentary cause, was injured, and died of his wounds on 24 June. The following month he had a chance for more substantial action. The battle of Roundway Down (13 July) had left Parliament vulnerable in the west. On 15 July Rupert was sent with a substantial army to help complete the Royalist conquest of the west country by capturing Bristol and Gloucester. He reached Bristol on 23 July, where he joined with Prince Maurice and the Cornish army. Rupert decided on an assault, and on 26 July the attack was launched by both armies. While Maurice stalled, Rupert's attack was successful, and by early evening the garrison of the city surrendered. For the siege of Gloucester, Charles himself joined the army, and overruled any idea Rupert had of another assault. When Essex arrived on 8 September, Charles realised he had a chance to cut Essex off from London, and defeat him on ground of his own choosing. In the event, neither side marched as fast as they could, and the first contingents of Essex's army entered Newbury on 19 September, only to be chased out by Rupert's advance guard. The following day saw the first battle of Newbury (20 September 1643). Rupert had command of the Royalist cavalry. His first role was to attempt to capture Wash Common, to allow a bombardment of the Parliamentary positions on Round Hill, which he did, but Round Hill itself never fell, and again the battle ended in a draw. The next day, Charles marched off to Oxford, while Rupert stayed to harry Essex on his march back to London.
Over the next winter, the Royalist position in the north weakened dangerously. Rupert, newly created earl of Holderness and duke of Cumberland was sent to deal with the problem, incidentally exposing himself to threat from his enemies at court, who including the Queen. He departed north on 6 February 1644, initially moving to Shrewsbury, but his first concern had to be Newark, threatened by a Parliamentary army some 7,000 strong. In his march to Newark, Rupert managed to raise 6,400 troops, with which he won the resulting battle of Newark (21 March 1644) after the rapidity of his march took the Parliamentary army by surprise. His next target was the relief of York, but first he was called back to Oxford (25 April-5 May), where he put forward a plan to defend Oxford by putting strong garrisons into a series of fortresses in the surrounding area, leaving a smaller cavalry force to reinforce anywhere that came under attack. If it had been adopted, this could well have prevented any Parliamentary attack, but as soon as Rupert left Oxford, the scheme was slowly abandoned.
The task now before Rupert was formidable. York had been under siege since 22 April, when the armies of the earl of Leven and Lord Fairfax arrived at the city. With him at Shrewsbury Rupert had only 8,.000 men, so he decided to march through Lancashire picking up reinforcements, and incidentally capturing Liverpool (11 June). Now with 14,000 men, he moved towards York. The situation there had just got worse. The garrison, under Newcastle, was only 4,800 strong, while the besiegers, now reinforced by the earl of Manchester, had some 30,000 men. Hearing that Rupert was on his way, the Parliamentary army formed up at Long Marston, where they though they could cover all of the approaches to York, but Rupert managed to cross over the River Ure and River Swale and outflank them, relieving York on 1 July. This was the high-point of his military career, and was soon followed by crushing defeat. Right from the start, the battle of Marston Moor (2 July 1644) went wrong for Rupert. He failed to deal properly with Newcastle and his troops, who had spend months under siege in York, and they thus turned up very late. Rupert's plan appears to have been to provoke a Parliamentary attack, but as evening arrived, he seems to have decided that the chance for a battle that day was over, and allowed his men to break formation to eat. At this point the Parliamentary forces attacked. The crisis came on the Royalist right, opposing Cromwell. Rupert, who had been eating when the fighting started, saw this, and charged into the fray against on this flank, which developed into a fierce melee that lasted until dark. Rupert himself found himself isolated amongst enemies, and forced to hide in a beanfield. This effectively left the control of the battle to Newcastle, but it was a lost cause, as Cromwell's victorious cavalry swept all before them. Rupert managed to get back to York, before heading for Chester (25 July) and Bristol (Late August). His reputation as a general suffered greatly from the defeat, but not as greatly as the Royalist cause in the north, now doomed by the loss of York.
Luckily for Rupert, Charles was happy enough with his victory over Essex in Cornwall that he failed to see the importance of Marston Moor. At a conference at Sherbourne Rupert was given a small force with which to attempt to draw off at least one of the Parliamentary armies currently gathering around Charles. He was thus not present at the second battle of Newbury, but soon rejoined Charles at Bath, before they returned to Oxford, where on 6 November Rupert was appointed general of the King's army, although at Rupert's own insistence the Prince of Wales (Charles II), was appointed commander in chief.
Rupert soon found his position as general undermined, in part by the King, who decided to give the Prince of Wales his own court at Bristol, which gave those Royalists in the west a perfect reason to ignore Rupert, who was unpopular with many Royalists, in particular Lord Digby, now Charles's chief advisor, and an enemy of Prince Rupert. The first effect of this was that the artillery at Oxford, required by Rupert at his Hereford base, failed to move until the end of April 1645 by which time the New Model Army was active, and prevented the movement. However, Rupert retained enough influence to affect the King's plans for the summer. While much of the council wished to move to the west, and confront the New Model Army while it was isolated, Rupert insisted on a march north to relieve Chester, and got his way. On 9 May, Charles, with his army, began their march north, leaving Fairfax and the New Model besieging Oxford. However, the Royalist plans were soon changed. The siege of Chester was abandoned, while news arrived that Oxford was not as well supplied as it should have been. The decision was made to provoke battle by capturing some Parliamentary stronghold. Leicester was chosen, and on 30 May Rupert stormed Leicester, which much as expected forced Fairfax to move north to retake the town.
The two armies met at the battle of Naseby (14 June 1645). Rupert commanded the Royal army, and initial did well. The ground chosen favoured him, but he was out thought by Fairfax, and eventually moved forward onto a more dangerous position, forcing his army to charge uphill, and leaving his artillery far behind. Worse, once the armies were lined up, Rupert went to command the charge of the right wing, abandoning his role as general. This time, his charge did not win immediate results, but eventually he broke Ireton's cavalry, but once again his cavalry then chased their broke foes off the battlefield, before finding the Parliamentary baggage camp and making a futile attack on it. Still, Rupert was able to regain control of his troops quicker than at Edgehill, although it still took him an hour. By the time he returned, the battle was lost, Charles attempting to rally the remaining cavalry, and the infantry surrendering in droves. Rupert was unable to persuade his cavalry to rejoin the fray, and they abandoned the field, only rejoining Charles at Leicester.
By the end of July, Rupert was in charge of the defence of Bristol, the last Royalist stronghold in the west, once staunchly Royalist. From there he wrote to Charles urging him to make peace, but his advice was, as would be expected, ignored. Rupert soon found himself with his own problems in Bristol, where he had 1,500 men to defend five miles of walls, as well as plague in the city. On 4 September Fairfax summoned him to surrender, and once Rupert refused, launched an assault on 10 September, which achieved in the same way as Rupert's own earlier attack. Faced with this, and the certain knowledge of defeat, Rupert, with the support of his officers, surrendered on terms. This was too much for Charles, and prompted by Digby he dismissed Rupert from all of his commands, and ordered him to leave the country. Rupert was furious, and determined to clear his name. For some time Digby was able to keep Charles and Rupert apart, but on 16 October Rupert managed to catch Charles at Newark, and was cleared of all blame by the Council of War. Despite this, Charles had turned against him, and to make a point replaced one of Rupert's supporters as governor of Newark, provoking a near-mutiny by Rupert and his supporters, which removed any effectiveness left in the army then with Charles, already suffering from low numbers and too many officers. Rupert remained in Charles's service until the end, marching out of Oxford on 22 June 1646, two days before the city surrendered, and was ordered into exile by Parliament.
On his exile, Rupert joined the Prince of Wales at St. Germain (July 1646), where he was appointed mareschal-de-camp, with command of the English troops in French service. While in exile he began a naval career, commanding a fleet sent to help Ormonde in Ireland in 1649, before relieving the Scilly Isles, still held by the Royalists. In 1652 he made a piratical cruise to the Caribbean, but in 1654 returned to Germany, settled into an exhausted peace after the Thirty Years War.
He returned to England on the restoration of Charles II, where he resumed a distinguished career. He played a part in the early development of English overseas commerce, as a patentee of the Royal African Company (1663), and charter holder for the Hudson Bay Company (1670). His main military duties were at sea. During the Second Anglo-Dutch War (1665-7), he served with Monck, although with little real success. Despite this, at the start of the Third Anglo-Dutch War (1672-4) he was vice-admiral, before being promoted to Admiral of the Fleet. In 1673 he suffered defeat at Schoonveldt (28 May 1673) and Texel (11 August 1673), but despite (or perhaps because) of that, he was created first Lord of the Admiralty (1673-9).