The York March, 1644
The fall of Selby in April 1644 was a major blow to the Royalist cause in northern England. It forced the Marquis of Newcastle to abandon his campaign against the Covenanter invasion in County Durham and withdraw to defend York, the northern Royalist capital, which now came under threat from Lord Fairfax and the Yorkshire Parliamentarians. As the Marquis withdrew towards York, the Earl of Leven pursued with the Covenanter army. On 20 April 1644, Leven joined forces with Lord Fairfax at Wetherby. The combined "Army of Both Kingdoms" marched to besiege York, arriving before the city on 22 April.
The Siege of York, April-July 1644
The besiegement of York was a formidable undertaking. Situated at the confluence of the River Ouse and the smaller River Foss, the city commanded the only bridges over the Ouse between Selby and Boroughbridge, making encirclement difficult. The Foss had been dammed close to its confluence with the Ouse shortly after the Norman Conquest, causing the river behind to form a large lake, known as the King's Fishpond, that protected the north-eastern approaches. The city itself was defended by a continuous circuit of Roman and medieval walls built upon an earthen rampart. Although some of its defences had become ruinous by the first half of the 17th century, King Charles ordered that they should be repaired and strengthened during his four-month stay at York in 1642. An outer ring of earthworks and forts was constructed beyond the walls for additional protection and cannon were mounted on the city's four main gates (or "bars") and on the castle which dominated the southern defences. The garrison was well supplied with provisions and was fully manned after the arrival of the Marquis of Newcastle's northern army on 18 April 1644.

The besieging armies settled around the city in a great arc, with Lord Fairfax's army to the east, the Scots to the south and west. A bridge of boats was constructed over the River Ouse at Acaster Malbis a few miles south of York to allow communications between the two armies. Initially, the sector to the north between the Ouse and Foss was left open except for occasional patrols. Before the siege could begin in earnest, the Allies had to secure the surrounding country. Stamford Bridge was captured on 24 April but Allied attacks on Cawood Castle were repulsed. Raiders from the Royalist garrison at Pontefract threatened Allied positions to the south of York while Sir Hugh Cholmley sent raiders from Scarborough to harass those to the east. To the north, the Marquis of Montrose and Sir Robert Clavering captured Morpeth Castle, forcing Lord Leven to send troops from the siege to secure his lines of communication with Scotland. But gradually the Allies consolidated their position. Sir John Meldrum finally captured Cawood Castle on 19 May and outposts were established to contain the Royalist raids.
Early in June 1644, the Earl of Manchester arrived at York with the army of the Eastern Association, having secured Lincolnshire for Parliament with the capture of Lincoln and Gainsborough. Manchester's arrival brought the total number of Allied troops before York to 25,000. The Eastern Association occupied the previously unguarded northern approaches to complete the encirclement of the city. A second bridge of boats was constructed across the Ouse at Poppleton to establish communication between the armies.
Around the same time, Sir Henry Vane arrived with orders from the Committee for Both Kingdoms for the Allied commanders to march against Prince Rupert, who was gathering a Royalist army across the Pennines in Lancashire. The generals were reluctant to split their forces, however, and Vane eventually acknowledged that they were right to continue the siege. During Vane's conference with the generals, the possibility of deposing King Charles was openly discussed for the first time. The generals unanimously rejected the idea, and it is possible that the Earl of Manchester's disillusionment with the Parliamentarian cause began as a result of these discussions.
The first Allied artillery battery was established in Lord Fairfax's sector and began bombarding the walls of York on 5 June. Two days later, the Covenanters stormed three outlying forts that covered the western approach to the city, two of which were captured. This setback prompted the Marquis of Newcastle to open negotiations for surrender. After an exchange of correspondence with the Allied commanders, a cease-fire was arranged for 14 June when commissioners from both sides met to discuss terms. They were unable to reach agreement. The Allied leaders suspected that Newcastle was playing for time and pressed ahead with plans to carry the city by storm.
Realising that the walls of York were too strong to be breached by artillery fire, the Allies initiated mining operations at two points: in the south-east at Walmgate Bar and in the north-west near St Mary's Tower. They planned to explode the mines and assault the two breaches simultaneously. On 16 June, however, the mine at St Mary's was exploded prematurely. Major-General Crawford sent 600 Eastern Association infantry through the breach, but the attack was carried out in isolation. The Royalists counter-attacked and secured the breach. The attackers were cut off and forced to surrender before the Allies could support the assault, suffering up to 300 casualties. No further attempts were made to storm the city. Meanwhile, Prince Rupert's relief force was preparing to lift the siege of York.
The York March, 16 May-1 July 1644
The threat to York from the allied Parliamentarian and Covenanter armies came at a time when the King's central Oxford army had been forced onto the defensive after the Royalist defeat at the battle of Cheriton. Prince Rupert was recruiting and directing military operations in Wales, but hurried south to a council of war at Oxford on 25 April 1644, where the defence of the Royalist capital was discussed. Rupert advised the King to strengthen the ring of fortresses around Oxford and to support them with a mobile cavalry force. With the Royalist capital secure, Prince Maurice could complete the conquest of the west while Rupert himself went north to assist the Marquis of Newcastle at York. Rupert hoped to raise the siege of York and rejoin the King before the summer was out. Early in May, Rupert returned to Shrewsbury to continue his preparations.

Prince Rupert marched from Shrewsbury on the first stage of the "York March" on 16 May 1644 with three cavalry regiments, five regiments of foot and a regiment of dragoons. He could not advance directly to York because he needed to gather reinforcements along the way and to secure Lancashire for troops returning from Ireland. Rupert was joined by the Earl of Derby, whose considerable local influence was expected to help in raising recruits in Lancashire. On 23 May, they were joined by Lord Byron with four regiments of horse and four of foot from Chester. In order to secure a crossing of the River Mersey, Rupert stormed the Parliamentarian outpost at Stockport on 25 May. The garrison fled as soon as the Royalist assault was launched. After his troops had plundered Stockport, Rupert by-passed the well-fortified town of Manchester and advanced on Bolton on 28 May.
The Storming of Bolton
Bolton was known as the "Geneva of the North" because of its austere Puritanism. Its garrison was around 4,000 strong after Colonel Alexander Rigby abandoned the siege of Lathom House to join Colonel Shuttleworth behind Bolton's earthen walls. Rupert had not expected to find the town so strongly defended. Despite heavy rain, however, he ordered four regiments to attack immediately. They were beaten back with casualties of around 300 men, including Colonel Russell, the commander of Rupert's own regiment of foot, who was wounded.
Rupert ordered a second attack, which was led by the Earl of Derby. The Royalists were enraged because Colonel Shuttleworth's men had hanged one of the soldiers taken prisoner during the first attack, apparently believing that he was an Irish Catholic. Although two of Rupert's infantry regiments had been released from service in Ireland by the signing of the Cessation of Arms, all the soldiers were English. However, Sir Thomas Tyldesley's regiment had been recruited mainly from Lancashire Catholics and regarded the hanging as an affront to their religion. Fuelled by sectarian anger against the Puritans of Bolton, the Royalists successfully stormed the walls and carried the fight into the streets of the town. The assault was followed by the sack of Bolton and a notorious massacre during which at least 1,000 townsmen and soldiers were killed.
A few days after the storming of Bolton, Lieutenant-General George Goring and Sir Charles Lucas joined Rupert's march at Bury with 5,000 men of the Marquis of Newcastle's cavalry, detached when the northern army withdrew into York, and a number of infantry units drawn from garrisons in the Midlands.
The Siege of Liverpool
On 5 June 1644, Rupert advanced to Wigan, where the Royalist townspeople strewed flowers and green boughs to welcome him. With the exceptions of Manchester and Liverpool, most of Lancashire was now under Rupert's control. While an attack on the well-defended town of Manchester was likely to prove costly and time-consuming, the garrison at Liverpool was weaker and the port was strategically important as another potential landing place for troops returning from Ireland. Rupert sent an advance guard under Colonel Washington to reconnoitre the defences then followed with his main army on 7 June.
Liverpool was protected by a medieval wall and ditch running in an arc around the landward side of the town. A 13th-century castle dominated the southern defences. On 8 June, the Parliamentarian governor Colonel Moore rejected Rupert's summons to surrender and underlined his defiance by shooting the Royalist herald's horse. Rupert promptly ordered up siege artillery to began bombarding the town walls. At noon on 10 June, Rupert ordered an assault on the breach, but the Royalists were driven back after an hour's fighting. However, Colonel Moore realised that he could not continue the defence and, under cover of darkness, began to evacuate the garrison and its stores by sea. Next morning, while the evacuation was still in progress, Colonel Tillier's regiment spearheaded a second Royalist assault that succeeded in capturing the town.
The first part of Rupert's plan was complete. Most of Lancashire was under Royalist control and he had secured Liverpool as another landing place for the troops from Ireland. Rupert hesitated at Liverpool, unsure whether to proceed to York or to turn south to be near the King, who was surrounded by advisers whom Rupert mistrusted. He also needed time to recruit troops, consolidate his army and complete the subjugation of Lancashire. However, around 19 June, Rupert received an ambiguous despatch from the King which he interpreted as ordering him not only to relieve York but also to fight the combined Scots and Parliamentarian armies that besieged it.
The Approach to York
With an army now 15,000 strong, Prince Rupert set out on the final stage of the York March immediately after receiving the King's despatch. From Liverpool, he marched via Lathom House to Preston, arriving on 23 June 1644, and started across the Pennines. Leaving a small garrison at Clitheroe, Rupert arrived at Skipton Castle on 26 June where he halted for two days to send messengers into York and to allow his army time to prepare for battle.

On 29 June, Rupert advanced to Denton Hall near Ilkley, the residence of the Fairfaxes. The following day, he arrived at Knaresbourough, fourteen miles west of York. Realising that he was heavily outnumbered, Rupert planned to avoid engaging the Army of Both Kingdoms until he had joined forces with the Marquis of Newcastle's infantry that was garrisoned in York. On 30 June, Rupert sent an advance guard of cavalry eastwards from Knaresborough to give the impression that he was advancing directly on York. The Allied generals responded by concentrating their forces on Marston Moor in order to block Rupert's apparent line of march. However, Rupert took the main body of his army north-eastwards from Knaresborough in a 22-mile flanking march. He crossed the River Ure at Boroughbridge on the morning of 1 July, continued on to cross the Swale at Thornton Bridge then marched down the eastern bank to approach York from the north. Late in the evening, Rupert's forces drove off the Eastern Association dragoons guarding the bridge of boats over the River Ouse at Poppleton, thus securing the only crossing of the river north of York.
The speed of Rupert's manoeuvre completely outwitted the Allies. The siege was raised and the defenders of York swarmed out to plunder the abandoned Scottish and Parliamentarian siege lines. Rupert's main force made camp in the Forest of Galtres while his cavalry secured the approaches to York. Rupert rode with his advance guard to reconnoitre the positions of the three Allied armies drawn up on Marston Moor.
Sources:
A.H. Burne & P. Young, The Great Civil War, a military history (London 1958)
S.R. Gardiner, History of the Great Civil War vol. i (London 1888)
Peter Gaunt, The Cromwellian Gazetteer (Stroud 1987)
Stuart Reid, All the King's Armies (Staplehurst 1998)
P.R. Newman, Atlas of the English Civil War (London 1985)
John Tincey, Marston Moor 1644 (Osprey 2003)
P. Young and W. Emberton, Sieges of the Great Civil War (London 1978)