sentences:  The Royalists specifically identified his countermining as the reason for lifting the siege.The Royalist artillery proved inadequate to the task of siege work, and the 300–400 large cannon balls and 20+ mortar bombs that were fired on the city failed to blow any major breach in the walls, start any significant fires or cause more than a handful of casualties.Although the failure at Gloucester adversely affected Royalist morale, the campaign presented Charles with an opportunity to inflict a decisive blow against his enemy.