After 1603 England and Scotland had been two different kingdoms ruled by the same king. Their legal systems, parliaments, nobility and other state systems had remained quite separate, but the personal union of the kingdoms in the body of the same king appeared to be firm.
Then in 1649 the English tried King Charles I for treason against England, found him guilty and chopped off his head. This man was also the King of Scots and the Scottish people did not take kindly to having their king executed. England declared itself to be a republic under Parliament, but Scotland opted to remain a kingdom and hailed the eldest son of the executed king to be their King Charles II. It was unclear if the two nations would go their separate ways as in the past or if they would again unite. The question led to the Battle of Dunbar.
Almost as soon as Charles entered Edinburgh, the English gave their army orders to march into Scotland and expel the 19 year old prince they termed “Mr Charles Stuart”. The English believed that Charles would not be content to rule only Scotland but would, sooner or later, make a play for England. They decided to strike first.
Inevitably it was Oliver Cromwell who led the English army, he took with him Lambert who had fought at Preston, and the remarkably able George Monck. On 22nd July Cromwell crossed the border with 20,000 men, supported by a fleet cruising off the coast. Cromwell was determined to crush the Scottish army, capture Edinburgh and force the Scots to get rid of Charles.
Facing Cromwell was David Leslie, victor of the Battle at Newburn Ford. As a professional soldier, Leslie had been fighting in the Swedish army while Cromwell was still a farmer in East Anglia. Leslie had an army of some 16,000 men, most of them raw recruits. Realising he could not face Cromwell in open battle, Leslie opted for a grinding summer of attrition. His first move was to strip the countryside bare. People, livestock and supplies were packed into the cities and fortresses so that the English could not get at them.
Then Leslie turned to his army’s one true strength. If his men were inexperienced at fighting, they were experts at marching. When Cromwell attacked Edinburgh from the east he found himself faced by strong defences manned by Leslie’s Scots. When he marched on Leith, Leslie got there first and manned the defences. When Cromwell marched far to the west in a feint then came back to attack Edinburgh, the Scots again got there first.
By the end of August, Cromwell had had enough. His army was footsore and hungry. Supplies were running out and disease was rampant. Barely half of Cromwell’s army was fit for service. On 1st September Cromwell retreated to the fortified harbour of Dunbar, unloaded his remaining supplies from the fleet and allowed his troops a day of rest and full rations. Then he gave the order to march out of Dunbar and head south towards England.
Again, Leslie had got there first. The entire Scots army was drawn up on the formidable Doon Hill, blocking the road south.