On the 11th June 1685 the exiled Duke of Monmouth, illegitimate son of Charles II, landed at Lyme Regis in Dorset with a small force in an attempt to topple the new Catholic king James II. Monmouth was popular with a large section of the English people and many would support his rebellion in an attempt to recover religious and political rights which had been progressively eroded since the Restoration of Charles II.

This was to be a concerted effort between Scots and English, for the Duke of Argyll had set sail from Holland in May to initiate a rebellion in Scotland. But the planning was inadequate, their invasion preparations had been discovered by the crown and Monmouth's forces were few in number and poorly equipped. Argyll's Scottish rebellion was stifled almost before it could begin and within 36 hours the news of Monmouth’s landing had reached the king and his military commanders in London. The rebels' only chance was to raise, equip and train forces as they marched and to rapidly secure Bristol, England's second city, before the royal army could counter them.