The first advance of the Parliamentarians drove out the royalists from the Stand in the Park which they had occupied; but the besiegers seem at first to have greatly underrated the difficulty of their task, not because they expected to take the House by storm, but thinking it was so poorly provisioned that it might be easily starved into surrender. As a matter of fact, however, Lathom was well stocked with food, and for a time at least the blockade was so incomplete that supplies could easily be brought in. Moreover the difficulty of the ground for siege operations soon became apparent, and the nearer the lines were drawn to the walls the more danger was incurred from the marksmen on the Towers. The garrison was not content merely to look on at the attack but soon began to make sorties which greatly harassed the besieging force. On Tuesday, March 12, Captain Farmer led out 100 foot and the 12 horse which was all the garrison possessed, attacked the besiegers' works, and slew several of them, taking six prisoners. The following Sunday night, Captain Chisenhale sallied out from the rear gate with 30 men, and put the Parliamentarians to ignominious flight. The accounts of these sorties are probably exaggerated, and the number of the besiegers who were killed is certainly placed much too high; but the attack was not pressed with very much resolution. Much of the firing against the House was wild, and large amounts of ammunition were wasted;[129] though it is evident that a good deal of damage was done to the buildings by cannon shots. The besiegers' most successful weapon was a large mortar which was loaded with grenades or with eight pound stone bullets and did considerable execution. One shot falling into an old court destroyed most of the buildings which surrounded it; and another struck one of the Towers and broke down a large clock. Towards the end of March a message came from the Earl of Derby to Sir Thomas Fairfax, desiring free passage for his Lady and children from the House; but the garrison realising that Lord Derby knew nothing of the provision which had been made for a siege, or of the successful defence which was being carried on, resolved to take no notice of it. A formal acknowledgment was sent to Sir Thomas Fairfax, and a messenger was sent to Lord Derby who was then at Chester, to acquaint him more exactly with the state of things in Lancashire.