No sooner was the city taken than Rupert unwillingly turned back to Oxford. During the siege he had received letters from the King, urging him to hasten northward, but ere its completion the state of affairs was changed. Reading was in dire peril, and its Governor, Sir Arthur Aston, protested desperately to the Prince: "I am grown weary of my life, with perpetual trouble and vexation." In his garrison he seemed to have no confidence: "I am so extremely dejected with this business that I do wish, with all my heart, I had some German soldiers to command, or that I could infuse some German courage into them. For your English soldiers are so poor and base that I could never have a greater affliction light upon me than to be put into command of them."[[11]] The report of the Secretary Nicholas was not more comforting: "I assure your Highness it is the opinion of many here that, if Prince Rupert come not speedily, Reading will be lost!"[[12]] And finally, a peremptory command from the King for his instant return left the Prince no room for hesitation.

But with all his haste Rupert came too late. Aston had been incapacitated by a severe wound, and the command had fallen to his subordinate, Colonel Fielding. Ignorant of the King's long delayed advance to his relief, Fielding made a truce with Essex, in order to treat; consequently, when the King and Rupert arrived and fell upon Essex, Fielding could not, in honour, sally to their assistance. The relief party perforce retired, and Rupert sent to demand of Essex the name of a gentleman who had very valiantly attacked him in the retreat.[[13]] After this failure, there was nothing left but to surrender, and Fielding accepted Essex's permission to march out with the honours of war. But Essex was unable to prevent a breach of the articles by his soldiers, who attacked and insulted the Royalist garrison. This faithless conduct was bitterly remembered by the Royalists, and subsequently repaid in kind at Bristol and Newark. As for the unfortunate Fielding, he was tried by court-martial, and condemned to death for his untimely surrender of his charge. But Rupert, who fully understood his difficult position, was resolved that he should not suffer, and urged the young Prince of Wales to plead with the King for his life.[[14]] The little Prince's intercession prevailed, and Fielding was spared. Throughout the rest of the war he served as a volunteer, but, though he displayed great gallantry, his reputation never recovered the unfortunate miscarriage at Reading.

The vicinity of Essex's army detained Rupert for some time at Oxford. From that centre he and his picked troops carried on an active guerilla warfare, scouring the country on all sides. "They took many prisoners who thought themselves secure, and put them to ransom. And this they did by night marches, through unfrequented ways, often very near London." At the same time Rupert had to attend to a voluminous correspondence with his officers in all parts of the country. The generals, Crafurd, Newcastle, Maurice, and others demanded his orders. Lord Northampton appealed to him for relief from the exorbitant demands made on his tenantry by Colonel Croker.[[15]] From all sides came the usual complaints about quarters, and supplies of provisions or ammunition. Sir William Vavasour had a more unusual grievance. He commanded in Wales, under Lord Herbert, but Lord Herbert, being a Roman Catholic, could not openly exert his powers for fear of prejudicing the King's affairs; and Digby presumed to send orders to Vavasour. "How to behave myself in this I know not," wrote the distracted Colonel to the Prince. "Nor do I understand in what condition I myself am. My Lord Herbert is General, and yet all despatches are directed to me; which is not very pleasing to his Excellency."[[16]]

That Digby's intrigues were already beginning to disturb the King's councils is apparent from a sympathetic letter addressed by Nicholas to Rupert. Evidently the Prince had expressed some indignation at the vexatious interference of incapable persons. "The King is much troubled to see your Highness discontented," says Nicholas, "And I could wish that some busybodies would not meddle, as they do, with other men's offices; and that the King would leave every officer respectively to look after his own proper charge; and that His Majesty would content himself to overlook all men, and see that each did his duty in his proper place; which would give abundant satisfaction, and quiet those that are jealous to see some men meddle who have nothing to do with affairs."[[17]] But in spite of this plain speaking, the divisions which were to prove so fatal to the cause, were as yet but in embryo. Rupert was still the hero of the hour, still all powerful with his uncle, when he was near him. His next exploit was to raise his reputation yet higher.

In the middle of June, Rupert accomplished his famous march to Chalgrove Field. Intending to beat up Essex's quarters and to capture a convoy of money, he left Oxford on a Saturday afternoon with a force of some two thousand in all, horse and foot. Tetsworth was reached at 1 a.m. and, though all the roads were lined by the enemy, who continually fired upon the Royalists, Rupert marched through, forbidding any retaliation. By 3 a.m. he was at Postcombe, where he surprised several houses, and took some prisoners. Two hours later he reached Chinnor, and had surrounded and entered it before the Parliamentary soldiers were even aware of his presence. There, many of the enemy were killed and a hundred and twenty taken prisoners. But, unfortunately for Rupert, the noise of the conflict reached the very convoy he was come to seek, and it was saved by a detour from its intended route. Finding that he had missed the object of his expedition, Rupert began a leisurely retreat, hoping to draw the enemy after him. In this hope he was not disappointed. A body of Essex's troops hastily followed him, and between seven and eight a.m. he was attacked by his pursuers. At nine o'clock on Sunday morning he halted in a cornfield at Chalgrove. First securing his passage over the Thames by sending a party to hold the bridge, he lined the lane leading to it with dragoons, and then attempted by a slow retreat to draw the enemy into it. They followed eagerly; but the Prince suddenly realised that only a single hedge parted him from his foes, and thereupon halted abruptly. "For," said he, "the rebels, being so neere us, may bring our reere into confusion before we can recover to our ambush." Seeing him halt, the enemy began to fire, and the impetuous Prince could contain himself no longer. "'Yea,' said he, 'their insolency is not to be endured.' This said, His Highness, facing all about, set spurs to his horse, and first of all, in the very face of the dragooners, leapt the hedge that parted him from the rebels... Every man, as he could, jumbled over after him; and as about fifteen were gotten over, the Prince drew them up into a front." It was enough. The enemy, among whom was Hampden, were both better officered and better disciplined than heretofore, but they could not stand before the charge of the terrible Prince. The skirmish was sharp but short; Hampden fell, and, after a valiant if brief resistance, his comrades fled. Rupert's friend, Legge, had been, "as usual", taken prisoner, but was rescued in the confusion of the Puritans' flight. The Cavaliers, after nearly fourteen hours in the saddle, were too weary for pursuit. Rupert quickly rallied them, held the field half-an-hour, and then marched towards home. In less than twenty-four hours he had made a circuit of nearly fifty miles, through the heart of the enemy's country; had taken many prisoners, colours, and horses, surprised two outposts, won a battle, and lost about a dozen of his men. And it is added: "The modesty of all when they returned to Oxford was equal to their daring in the field."[[18]] Two of his prisoners Rupert had left at Chalgrove, with a surgeon to attend their wounds; but they showed themselves so ungrateful for this consideration as to break their parole. Essex received Rupert's complaint of their dishonourable conduct in a soldierly spirit, and returned two Royalist prisoners in exchange.[[19]] Essex was indeed always a courteous foe. Some time after this incident Rupert's falconer and hawk fell into his hands, and were by him generously restored to the Prince. Rupert happened to be absent from Oxford at that period, but the Puritan general's courtesy was gratefully acknowledged by Colonel Legge.[[20]]

Rupert's next duty was to bring the Queen to Oxford, a matter of no slight importance; for not only was her personal safety at stake, but also that of her money, arms, and troops. Essex, as well as the Prince, set out to meet Her Majesty, and it was Rupert's object to keep his own troops always between Essex and the Queen. On July 1st he quartered at Buckingham, and early in the next morning some of his men were attacked by those of Essex, at Whitebridge. Rupert was in the act of shaving when the noise of the skirmish came to his ears. Half-dressed and half-shaved, as he was, he dashed out without a moment's delay, charged and scattered his foes, and then quietly returned to resume his toilet. Throughout this march he kept Essex on perpetual duty, harassing him by day and night, until, after some dexterous manoeuvring, he left him unexpectedly on Brickhill, and himself joined the Queen at Stratford-on-Avon. That night, says tradition, Queen and Prince were the guests of Shakespeare's grand-daughter. If this was really the case, Rupert doubtless regarded his hostess with deep interest; for all the Palatines could quote Shakespeare. On July 13th the King came to meet his wife at Edgehill, and King, Queen and Prince slept at Wroxton Abbey. On the following day they entered Oxford in safety. The Queen's arrival considerably changed the condition of the University. The colleges were populated no more by scholars, but by ladies and courtiers; Oxford was no longer a mere garrison, it was also a court. Chief among the noble ladies who attended the Queen, was the beautiful young Duchess of Richmond, only daughter of the King's dead friend, "Steenie," Duke of Buckingham. She it was whom her father had once destined to be Rupert's sister-in-law, as the bride of his brother Henry. But ere the bride was ten years old, both her father and her intended bridegroom had died untimely deaths, and the fair Mary Villiers was therefore brought up in the Royal family as the adopted daughter of the King. For her father's sake, and for her own, she had always been a petted favourite of her royal guardian, who called her "The Butterfly", a name derived from an incident which occurred when the lady was eleven years old. Once, dressed in her widow's weeds—she had been a widow at eleven—she had climbed a tree in the King's private garden, and had been nearly shot as a strange bird. But the courtier sent to shoot her perceived his error in time, and, at her own request, sent her in a hamper to the King, with a message that he had captured a beautiful butterfly alive; and the name clung to her ever after.[[21]] The King's affection for her and for the Duke of Richmond made it seem good to him to unite them in marriage, and the arrangement appears to have pleased all parties. Mary had disliked her boy-husband, Lord Herbert;[[22]] but the Duke she seems to have regarded with favour. Possibly his quiet and melancholy disposition supplied the necessary complement to her own merry and vivacious temperament. In 1636 the Queen had refused to have her in the Bedchamber, on the plea that her charms eclipsed all others; and now, in 1643, Mary Villiers was, at the age of twenty, in the prime of her beauty. Rumour said that she had won the heart of "the mad Prince," while the equally lively Mrs. Kirke had subjugated that of Maurice. A libellous Puritan tract represents Mrs. Kirke as extolling Maurice's "deserts and abilities," though she was forced to acknowledge that he "did not seem to be a courtier." But the Duchess assured her companions "that none was to be compared to Prince Rupert."[[23]] Nor was it only Puritans who commented on Rupert's admiration for the Duchess. The Irish Cavalier, Daniel O'Neil, "said things" in Ireland to Lord Taafe, after which he lost both the Prince's favour and his troop of Horse.[[24]] Rupert hotly resented the imputations cast upon him, and, had they been other than slanders, it is impossible to conceive that he and the Duke could have maintained their close and faithful friendship. The Duke, with his "haughty spirit", was not a man to dissemble, and his letters to Rupert are all full of solicitude for his welfare, and of sympathy and consolation for his troubles. Even in his hour of failure and ruin the Duke stood loyally by his side, though, in so doing, he was putting himself in opposition to his adored sovereign. Still it is certain that Rupert both felt and evinced a very strong admiration for the Duchess. "There will be a widow, and whose she shall be but Prince Rupert's, I know not," wrote a Cavalier, when the Duke's death was rumoured in 1655.[[25]] But the Duchess took for her third husband, not Rupert, but "Northern Tom Howard," whom she said she married for love, and to please herself; her two former marriages having been made to please the Court.[[26]] Most likely she had never really cared for the Prince, and had merely amused herself with a flirtation. She was, no doubt, proud of so distinguished a conquest, but she never disguised her friendship for her supposed lover, and she sent him messages by all sorts of people, in the most open way. "I had an express command to present the Duchess of Richmond's service to you,"[[27]] wrote Rupert's enemy, Percy, in July 1643.

The society of the Duchess could not detain the active Prince at Oxford, and within four days of his arrival there, he set out for a second attempt upon Bristol. The Royalist arms were prevailing in the West. A few days previously Nicholas had reported to the Prince the victory of Lansdowne, with the comforting assurance that "Prince Maurice, thanks be to God, is very well and hath received no hurt, albeit he ran great hazards in his own person."[[28]] Two days later Maurice arrived in Oxford, to obtain supplies of horses and ammunition for Ralph Hopton, who lay seriously wounded at Devizes. Thither Maurice returned with all speed, and, immediately on his arrival, took place the battle of Roundway Down. This was a brilliant victory for the Royalists, and the news was received in Oxford with much rejoicing; albeit for Rupert the joy was tempered with disgust at the credit which thereby redounded to Lord Wilmot.[[29]] These successes increased the Prince's desire to capture Bristol, then the second city in the Kingdom, and the key of all South Wales. Maurice and Hertford were now at liberty to assist him, and, on July 18th, he began his march with fourteen regiments of foot, "all very weak," and several troops of horse. Waller was the General of the Parliament now opposed to him, but Waller's troops had been in a broken condition ever since the victories of Hopton and Wilmot, and he retreated before Rupert's advance. On the 20th, Thursday, Maurice came to meet his brother at Chipping Sodbury, and joined his march. On Sunday they were within two miles of Bristol, and the two Princes took a view of the city from Clifton Church, which stood upon a hill within musket-shot of the porch. While they stood in the church-yard the enemy fired cannon on them, but without effect; seeing that their shot would be harmless, Rupert quartered some musketeers and dragoons upon the place. That night Maurice retired over the river to his own troops; and the same evening the enemy made a sally, but were repulsed.

On Monday morning Rupert marched all his forces to the edge of the Down, in order to display them to the garrison of Bristol; and Lord Hertford, who commanded the Western army, made a similar show upon the other side. About 11 a.m. Rupert sent to the Governor—Nathaniel Fiennes, a son of Lord Say—a formal summons to surrender. The summons was of course refused, and immediately the attack began. Long after dark Rupert continued to fire on the city. "It was a beautiful piece of danger to see so many fires incessantly in the dark from the pieces on both sides, for a whole hour together.... And in those military masquerades was Monday night passed."[[30]] Tuesday was spent in skirmishing, while Rupert went over the river to consult with Lord Hertford and Maurice. The result of this consultation was a general assault of both armies next morning. "The word for the soldiers was to be 'Oxford', and the sign between the two armies to know each other, to be green colours, either bows or such like; and that every officer and soldier be without any band or handkerchief about his neck."[[31]] The zeal of Maurice's Cornish soldiers nearly proved disastrous, for on Wednesday morning, "out of a military ambition", they anticipated the order to attack.[[32]] As soon as he heard the firing Rupert hastened to draw up his own men, but the scaling ladders were not ready. In consequence of this, the young Lord Grandison, to whom had been entrusted the capture of the fort, had made no impression, after a valiant assault which lasted an hour and a half, and during which he lost twenty men. For a short time he was forced to desist, but, speedily returning to the attack, he discovered a ladder of the enemy by which he was able to mount; only to find that he could not get over the palisades. In his third assault Grandison was fatally wounded, and his men, utterly discouraged, left the attack. At this point Rupert sent word that Wentworth had entered the suburbs, upon which Grandison retired to have his wounds dressed, and ordered his men to join Bellasys on the left. Instead of obeying this order they began to retreat; but were met by Rupert himself who led them back to the enemy's works. It was then that Rupert's horse was shot under him and he strolled off on foot, with a coolness which immensely encouraged the men. Having, after a while, obtained a new horse, "he rode up and down from place to place, whereever most need was of his presence, here directing and encouraging some, and there leading up others. Generally it is confessed by the commanders that, had not the Prince been there, the assault, through mere despair, had been in danger to be given over in many places."[[33]]

On the other side Maurice was equally active. He had directed his men to take faggots to fill the ditches, and ladders to scale the forts, but in their haste to begin the attack, they had forgotten both. The scaling party had therefore failed and retired. During the retreat "Prince Maurice went from regiment to regiment, encouraging the soldiers, desiring the officers to keep their companies by their colours; telling them that he believed his brother had already made his entrance on the other side."[[34]] Retreats seem to have succeeded under Maurice, for we are told by one contemporary that he earned from his foes the name of "the good-come-off."[[35]] In a short time his assurance was justified; Rupert sent word that the suburbs were entered, and demanded a thousand Cornish men to aid his troops. Maurice sent over two hundred, but presently came across the river himself with five hundred more. By that time the fight was nearly over, and Fiennes sent to demand a parley. The demand was a welcome one, for the Cavaliers' losses had been very heavy, especially in officers. Among the fallen were Grandison, Slanning, Trevanion and many more of famous and honourable name.

At five o'clock on the evening of July 26th, terms were agreed on between Fiennes and the Princes; Lord Hertford not being consulted in the matter. Fiennes was to march out at nine o'clock next morning with all the honours of war, and to be protected by a convoy of Rupert's men. Contrary to all expectation and custom, he marched out next morning at seven o'clock, two hours before the time arranged. The convoy promised by Rupert was not ready, and the Royalist soldiers, remembering Puritan perfidy at Reading, attacked and plundered the retiring garrison. The fault was none of Rupert's, but for all that he keenly felt the breach of faith. "The Prince who uses to make good his word, not only in point of honour, but as a matter of religion too, was so passionately offended at this disorder that some of them felt how sharp his sword was," wrote one of his officers.[[36]] The Puritans would fain have used the incident to blacken the Prince's character; but Fiennes himself generously acquitted his conqueror of all blame. "I must do this right to the Princes," he said; "contrary to what I find in a printed pamphlet, they were so far from sitting on their horses, triumphing and rejoicing at these disorders, that they did ride among the plunderers with their swords, hacking and slashing them; and that Prince Rupert did excuse it to me in a very fair way, and with expressions as if he were much troubled at it."[[37]]