Assheton was not slow to follow up the victory at Whalley. Two days later he marched on Wigan (April 22), which was occupied by Colonel Tyldesley with 9 troops of horse and 700 foot; Assheton had 2,200 horse and foot mostly belonging to the Manchester garrison, and the royalists were in no condition to resist superior numbers. They fell back on Lathom without fighting, and Assheton demolished all the out-works and fortifications at Wigan, burnt the new gates and posts, and made the townsmen swear not in future to bear arms against "King and Parliament."[104] Derby himself seems to have been at Prescot, but on Assheton advancing against him he retreated to Lathom, and then the Parliamentarians gradually moved northwards and westwards, driving the enemy before them. On hearing of the loss of Wigan, the Queen sent a message to Lord Derby not to engage the enemy again until she sent him reinforcement; but having waited for a fortnight in vain he was persuaded by Molyneux and Tyldesley to endeavour to hasten it in person. There is no doubt that the Queen at this time intended to invade Lancashire. She writes from York to the King on April 23 "my proposition is this--to detach from the body of the army 2000 footmen and 1000 horsemen, 200 dragoons and some cannon and to send them at once into Lancashire to join with Earl Derby and to clear out that county, which I hope can be done in ten or twelve days, and then come to join me at Newark"; and three weeks after this she writes again that the army was to march directly on Leeds, Bradford and Halifax. Derby was to return, to collect what troops he could, and remain on the defensive until "the army can march to Manchester which I hope will be soon; for I believe that Leeds being taken, the other two places will be inconsiderable, and so Manchester will come into play; which if we take it all Lancashire is yours."[105] These plans were, however, frustrated by the royalist defeat by Sir Thomas Fairfax at Wakefield in May; and there was no longer any hope of reinforcements to the Lancashire royalists from the Queen's army. Derby returned to Lancashire; and a rumour having come of a Scotch invasion by means of the Isle of Man, he was persuaded to sail thither to prevent it. Returning to Lancashire about the end of May, he hastily crossed the county with a very small following, and rode to Whitehaven, whence he took ship to the Isle of Man, landing there on June 15. The Countess of Derby and her children remained at Lathom House.[106]