During the English Civil War (1642–1651), Bristol was a key port on the west coast of England and considered strategically important by both Royalists and Parliamentarians.
[2] The town was well fortified by the Frome and Avon rivers, as well as a medieval castle, which had been bought by the corporation when the First English Civil War broke out in 1642, and during the Parliamentary defense, earthen artillery forts.
[4] Royal Fort House was built on the site of two bastions on the inside of the lines and three on the outside which were fought over during the English Civil War.
[1][page needed] A typical myth about Bristol during the civil war concerns its capture by Prince Rupert in July 1643.
Traditionally it has been accepted that Bristol was attacked by a Royalist army of up to 20,000 men and that William Waller had irresponsibly reduced the garrison to 1,500 infantry and 300 mounted troops, insufficient to man the defensive lines surrounding the city.