But the discontent and jealousy which were always rife among the soldiers and courtiers in Charles’ camp, broke out afresh when the King returned to Oxford after his failure to take Gloucester. From this moment, indeed, the firmness of Parliament and the factiousness and foolishness of the King’s party began slowly to reverse the fortunes of the war. Parliament obtained the assistance of Scotland, and Charles negotiated with the Irish Catholics. The alliance was fatal to his cause. Many of Charles’ supporters left him; the six peers fled back to Westminster. The covenant was concluded. A Scotch army crossed the border and co-operated with Fairfax and Leven in the north; Essex watched the King at Oxford, and was presently supported by Waller, who had been holding Prince Maurice in check in the west. The Queen, who was enceinte, and afraid of being besieged, now insisted on leaving Oxford (April 1644). She made her way safely to Exeter.

The Royalists abandoned Reading and fell back on Oxford, where measures were being taken for defence. Regiments were enlisted; trees were felled in Magdalen walks, and means were provided for flooding the meadows beyond. Batteries were erected at suitable points. One of these, at the north-east corner of the walks, was called Dover Pier (Dover’s Peer?), probably after the Earl of Dover, who commanded the new University Regiment. This regiment mustered for the first time on 14th May 1644 in Magdalen College Grove, and, along with the City Regiment, was reviewed on Bullingdon Green a few days later. The rise in the ground at the end of Addison’s Walk, which is still noticeable, is probably due to the high and strong causeway which we know led from the walks to the battery in the river.

The Parliamentarians advanced, Abingdon was evacuated by the Royalist army under Wilmot, and occupied by Essex. Charles was forced to withdraw all his forces to the north of Oxford. The King’s position was now so serious, that it was confidently reported in London that Oxford was taken and the King a prisoner. Another rumour ran that the King had decided to come to London, or what Parliament chiefly feared, to surrender himself to Essex. Presently, indeed, his own supporters advised this course, but His Majesty indignantly rejected the suggestion, saying that possibly he might be found in the hands of Essex, but he would be dead first.

As no help could be looked for from north or west, he determined to stay in Oxford and watch for an opportunity of fighting Waller or Essex separately. With this object in view he disposed his army so as to prevent the rebels from crossing the Cherwell or Isis, the foot holding the former and the horse and dragoons the latter. A series of smart skirmishes ensued. Some of Waller’s forces attempted to pass the Isis at Newbridge, but were repulsed. The next day (29th May), however, Essex crossed the Thames at Sandford Ferry with his whole army and quartered himself at Islip. On his way thither he halted on Bullingdon Green, “that the city might take a full view of his army and he of it.” He himself rode up within cannon shot, whilst parties of his horse skirmished about the gates, and gave the scholars and citizens an opportunity of trying their prowess. “It gave some terror to Oxon,” says Wood, “and therefore two prayers by his Majesty’s appointment were made and published, one for the safety of his Majesty’s person and the other for the preservation of the University and City, to be used in all the churches.” But there was no intention of making an assault upon the town. Essex was merely covering the passage of his baggage train. Whilst he was thus occupied and the scholars were making a sortie, Charles and Rupert ascended Magdalen Tower and watched the movements of the enemy. Next morning a determined effort was made by Essex to pass over the Cherwell at Gosworth Bridge, but he was repulsed by the musketeers with considerable loss. Essex being now on the east side of the river and cut off from communication with Waller, the King strove to avail himself of the opportunity of retaking Abingdon and engaging Waller singly.

But after an unsuccessful move against Abingdon, the design was abandoned, and the Royalist forces were once more concentrated on the north side of Oxford. Sir Jacob Ashley, Major-General of the Foot, himself took command at Gosworth Bridge, where, he perceived, Essex intended to force a passage. There he threw up breastworks and a redoubt, and succeeded in repulsing the enemy, who renewed their attacks from day to day and even brought up cannon to their support without avail. Meanwhile, however, Waller effected the passage of the Isis at Newbridge, quartered his van at Eynsham, and threatened the rear of the King’s army. Ashley was compelled to retire. Essex immediately threw his men across the Cherwell, and quartered them that night at Bletchington. His horse advanced to Woodstock. The King seemed to be enveloped by the opposing armies. But after making a demonstration against Abingdon, Charles slipped out of Oxford on the night of 3rd June. Marching out with six thousand men by S. John’s Road, he made his way along a rough crooked lane and got clear away to the north of the city. He left the Duke of York in the town, and promised, if the place was besieged, to do all he could to relieve it before it was reduced to extremity. But the town had scarcely enough provisions to stand a month’s siege.

A series of brilliant successes rewarded the perseverance of the King, for he now waited till Essex marched to attack Prince Maurice at Lyme, then turning on Waller, crushed his army at Copredy Bridge on the Cherwell, fourteen miles north of Oxford. After two days’ rest at Oxford, he followed up his success by pursuing Essex into Cornwall and gaining a complete victory over him there. But in the midst of these successes came the news of the disaster in the north. The star of Cromwell had risen where Rupert’s had begun to set, at Marston Moor. The battle of Newbury checked the King’s advance on London, and he withdrew once more to winter at Oxford (27th October 1644). He was much pleased with the progress that had been made with the fortifications. In order to carry on his operations against Waller and Essex, he had been obliged to denude Oxford of troops. But before leaving it he had provided for its safety. For Parliament had a strong garrison at Reading and another at Abingdon, and the danger of a siege seemed imminent. The inhabitants were therefore commanded to provide themselves with corn and victuals for three months, or to leave the town “as persons insensible of their own dangers and the safety of the place.” The safety of the place having been secured, the garrison had felt themselves strong enough to send out a force to the relief of Basing-House. The objections of the governor, Sir Arthur Aston, who had succeeded Sir William Pennyman in that office, were overruled. Colonel Gage made a dash from Oxford, relieved the Marquis of Winchester and returned safely to Oxford after having performed one of the most brilliant of the minor feats of arms that occurred during the war. Charles, on his return, appointed him Governor of Oxford, in place of Sir Arthur Aston, who had broken his leg. Gage, who is buried in the Cathedral, was killed shortly afterwards at Culham Bridge in an attempt to surprise Abingdon.

In the spring of 1645 Oliver Cromwell appeared in the parts about Oxford. He was in command of some cavalry, and the object of his movements, in conjunction with those of Sir Thomas Fairfax, was to prevent Prince Maurice from removing heavy guns from Oxford to Hereford, and thereby to disarrange Charles’ plan for an early campaign. Cromwell routed Northampton at Islip. A party of the defeated Cavaliers took refuge at Bletchington House. Cromwell called upon the governor, Windebanke, to surrender. Deceived by the sheer audacity of the demand, and moved, it is said, by the timorous entreaties of a party of ladies from Oxford whom he was entertaining at Bletchington, he yielded. Windebanke paid dearly for his weakness. He was shot in the Castle garden on his return to Oxford. Cromwell swept round the city and defeated Sir Henry Vaughan at Bampton. The Parliamentarians had now achieved their object. They moved away from Oxford. In a few weeks they were back again, and the new fortifications of the city were at length put to the test. The siege was heralded by the appearance of some scattered horse near Cowley on 19th May. Thence they, with other horse and foot, passed over Bullingdon Green to Marston, and showed themselves on Headington Hill. On the 22nd Fairfax sat down before Oxford. He threw up a breastwork on the east side of Cherwell, and constructed a bridge near Marston, across which he passed some regiments. Cromwell was commanding at Wytham and Major Browne at Wolvercote. The most considerable incident that occurred during the fifteen days’ siege was a successful sortie in the direction of Headington Hill, which was made by Colonel William Legge, the governor of the town. Then Fairfax raised the siege and moved north; a few weeks later the fateful battle of Naseby was fought. Thereafter the King finally made his way to Oxford from Newark. Here for a while he was safe; but in the spring Fairfax marched upon Oxford. The King was driven from his last refuge. At three in the morning of 27th April, disguised as a servant, with his beard and hair closely trimmed, he passed over Magdalen Bridge in apparent attendance upon John Ashburnham and a scholar, one Hudson, “who understood the byeways as well as the common, and was indeed a very skilful guide.” “Farewell, Harry,” Glenham called out to his sovereign, as he performed the governor’s duty of closing the gates behind him. Charles’ departure was kept so secret that Fairfax, who arrived before Oxford on the fifth day after, sat down before the city, and made his circumvallation before he knew of it.

The Duke of York and all the King’s Council remained shut up in Oxford. Fairfax found the city well prepared for a siege.

“The rising ground to the north was protected by many strong bulwarks flanking one another. Round about the line, both upon the bulwarks and the curtain, was strongly set with storm poles. Outside the ditch was a strong palisade beyond which were many pits dug so that a single footman could not without difficulty approach to the trench. Within the city were 5000 foot, and the place was well supplied with stores. All this strength being apprehended and considered by Sir Thomas Fairfax, he concluded that this was no place to be taken at a running pull, but likely rather to prove a business of time, hazard and industry.”

Accordingly he proceeded to make a fortified camp on Headington Hill, to make a bridge over the Cherwell near Marston, and establish a post between the Cherwell and Isis on the north for the main body of his troops. Lines were drawn from Headington to S. Bartholomew’s common road, and from thence to Campus pits. A memento of the siege, a cannon shot which is said to have struck the gateway tower of S. John’s College, is preserved in the library of that college.