By July 1645 the Royalists had lost control of much of the country, having suffered two successive summers of major defeats. In 1644 the north of England was lost as a result of defeat at Marston Moor and then, in June 1645, the parliamentarians destroyed the main royalist field army in the decisive victory at Naseby. The King now had only one effective field army, the Western army, consisting of some 7,000 troops under General George Goring. Parliament had the formidable New Model Army commanded by Sir Thomas Fairfax, as well as the smaller force of the Western association under Major-General Edward Massey; the Northern association under Colonel-General Sydenham Poyntz; as well as the support of a large Scottish Covenanter army in the north.

For the Royalists to maintain a presence in the field it was essential for the forces which remained with the King following Naseby, and those under Goring to combine. However, in July Goring was laying siege to a fiercely resistant Taunton and was in no position to march to the King, and Charles, at Raglan in South Wales, inexplicably made no attempt to join him.

Towards the end of June, once the town of Leicester had been retaken from the royalists in the days after Naseby, Fairfax began a march into the South West to the relief of Taunton. This was the last region almost wholly under royalist control and by far the wealthiest and most populous. Fairfax had first to challenge and destroy the last Royalist field army to both relieve the pressure on Taunton and open up the Royalist garrisons in the region to parliamentarian assault.

Obliged to take an indirect route to avoid Royalist garrisons, Fairfax forced marched his army south as far as Dorchester before turning north-east to approach Taunton. Arriving at Beaminster on 4th July Fairfax was informed that Goring had raised the siege at Taunton and was marching for Yeovil. Goring may have chosen to abandon the siege on hearing of the approach of Fairfax’s army, now some 14,000 strong having been joined by Massey’s troops. If so it is questionable why he chose to approach Yeovil, which was so much closer to Fairfax’s position. But Goring was a resourceful commander and feigning a return to Taunton he persuade Fairfax to divide his forces sending 4,000 troops towards the town, thus ensuring that when an engagement occurred Goring, though still out numbered, was in a far more competitive position. But this was not enough to avoid defeat.

Following the success at Langport the New Model could work systematically through the South West, reducing Royalist garrisons and thus removing the King's ability to continue the war.