Having declared his allegiance for the King, Hopton was instrumental in organising support for the Royalists in the south west of the country.  Waller was not idle either.  First forming a regiment of horse, then capturing Portsmouth in July 1642.

Initially, Hopton drove the Parliamentarians out of Cornwall in 1642, and then defeated Ruthin at the Battle of Braddock Down in January 1643.  Having displayed his undoubted ability, Hopton then became responsible for Royalist efforts in both Cornwall and Devon.  Marching towards the border with Devon, Hopton soundly beat the Earl of Stamford at Launceston in April, and again at Stratton in May.

Meanwhile, Waller’s cavalry force were part of the Parliamentarian force heavily beaten by the King at Edge Hill in October 1642.  Returning to Wessex, Waller returned to winning ways by capturing the historic towns of Winchester and Chichester, as well as the castles at Farnham and Arundel.  

Having been made Major-General of the West, Waller switched his attentions to Bristol; securing the port for Parliament.  Having done so, he then beat Herbert at Highnam and proceeded to threaten Royalist supporting Wales.  Losing to Prince Maurice on the English/Welsh borders at Ripple Field, Waller withdrew southwards into Gloucestershire and then Somerset. 

Having left Cornwall and Devon secure, and working in co-ordination with Prince Maurice and the Marquis of Hertford, Hopton turned his attention towards the Parliamentarian Western Army under Waller, by moving up into Somerset.  As a result, the two armies met just outside of Bath at Lansdown, where once again Hopton proved victorious.  However, Sir Bevil Grenville the senior Cornish commander was killed, and Hopton badly wounded.

Waller sensing his opportunity to strike back, proceeded to chase the Royalists through Somerset and Wiltshire.  The Royalist army was still nominally under the command of Hopton, who decided to make a stand at Devizes.  Lord Wilmot’s relieving cavalry force then fought a classic cavalry action at Roundway Down, beating the opposition horsemen through use of terrain and outflanking moves.  The Parliamentarian infantry were then subject to a co-ordinated attack by Hopton’s infantry and Wilmot’s cavalry, with Waller making a fortuitous high-speed escape.  As a result, the Parliamentarian Western Army ceased to exist, and allowed Hopton to move his forces towards the Parliamentarian held port of Bristol.