On 14 June 1645, Charles's main army was decisively beaten at the Battle of Naseby by the New Model Army under Sir Thomas Fairfax.
The King then withdrew to Hereford, hoping for more reinforcements from Wales and Ireland.
Early in July 1645, he lodged at Raglan Castle in Wales.
On 10 July his army in the west of England under Lord Goring was heavily defeated at the Battle of Langport, and news also reached Charles that an army of Covenanters was marching south.
At the beginning of August 1645, Charles left Raglan with some 2,500 men, marching northwards along the Welsh border in the hope of rallying more Royalists to his cause in the north of England.
He reached Doncaster on 18 August, where he had news that both the Parliamentary Northern Association army and a force of Covenanter cavalry were moving towards him.
He quickly withdrew to Newark and then to Oxford, by way of a punitive attack on Huntingdon, Oliver Cromwell's home town and Parliamentary base.

On 30 August the King marched to the assistance of his forces at Hereford, by now under siege by Lord Leven's Covenanters, but as the royal army approached news reached Leven of Montrose's victory on 15 August at the Battle of Kilsyth.
He abandoned the siege of Hereford, marching north, so that Charles was able to occupy the town on 4 September.
 The King returned to Raglan, where some two weeks later he received news that Prince Rupert had surrendered Bristol.
On 14 June 1645, Charles's main army was decisively beaten at the Battle of Naseby by the New Model Army under Sir Thomas Fairfax. The King then withdrew to Hereford, hoping for more reinforcements from Wales and Ireland. Early in July 1645, he lodged at Raglan Castle in Wales. On 10 July his army in the west of England under Lord Goring was heavily defeated at the Battle of Langport, and news also reached Charles that an army of Covenanters was marching south. At the beginning of August 1645, Charles left Raglan with some 2,500 men, marching northwards along the Welsh border in the hope of rallying more Royalists to his cause in the north of England. He reached Doncaster on 18 August, where he had news that both the Parliamentary Northern Association army and a force of Covenanter cavalry were moving towards him. He quickly withdrew to Newark and then to Oxford, by way of a punitive attack on Huntingdon, Oliver Cromwell's home town and Parliamentary base.
On 30 August the King marched to the assistance of his forces at Hereford, by now under siege by Lord Leven's Covenanters, but as the royal army approached news reached Leven of Montrose's victory on 15 August at the Battle of Kilsyth. He abandoned the siege of Hereford, marching north, so that Charles was able to occupy the town on 4 September.  The King returned to Raglan, where some two weeks later he received news that Prince Rupert had surrendered Bristol.
Siege of Chester