The Siege of Corfe Castle.
Lady Mary’s response rather surprised Sir Walter. Instead of meekly opening the gates of Corfe, Lady Mary and her maids manned the Castle’s cannons and unleashed a barrage of cannon fire at the invading roundhead force. Sir Walter and his men swiftly departed, having decided reinforcements were in order. Meanwhile, Lady Mary sent a messenger to the nearest royalist forces asking for extra men to bolster Corfe’s defenses. A Captain Robert Lawrence answered the call, and soon Lady Mary had an additional 80 men, who she placed in the Middle Ward of the castle, while she took command of the Upper Ward.
Lawrence’s reinforcements were just in time. On June 28, 1643, Sir Walter and his men returned. This time, he brought three Captains with him named Sydenham, Scott and Jarvis and a force of 600 men. For six weeks, Lady Mary and her men held Corfe. According to the Mercurius Rusticus Lady Mary, her daughters and servants saw off attempted invasions of the castle by “heaving over stones and hot embers” onto parliamentary troops trying to scale Corfe’s walls with siege ladders. An estimated 100 men were killed and wounded because of their efforts.
Finally, Sir Walter gave up and returned to the parliamentary stronghold of Southampton, giving “Brave Dame Mary” as she had become known time to regroup. However, on December 28, 1644, Lady Mary received another blow. She learned that her husband Sir John had been killed fighting for the King. The following year, the first round of the war was over when the Roundheads defeated the King’s forces at the Battle of Naseby. But still, Corfe held firm. However, at the end of the year, Parliament sent more troops under the command of Colonel John Bingham to force the castle’s garrison to submit.
Soon afterward, Lady Mary lost Corfe. However, this was not because her forces were defeated but because the castle was betrayed from within. One of Lady Mary’s officers a Colonel Pitmen led a party of Parliamentarians into the castle via a sally gate. The Roundheads had reversed their jackets to disguise themselves. By the time the ruse was discovered, Corfe had been taken. Lady Mary was forced to surrender. Bankes family legend says she defiantly threw the family’s treasures down the castle well but was allowed to keep the seal and keys to the castle in recognition of her bravery. After Corfe was taken, the Parliamentarians blew it up with gunpowder. The Bankes family would never live there again.
A popular story tells how in early 1646, shortly before Corfe fell, a small royalist force, rather ironically led by young royalist officer named Cromwell slipped through the lines of parliamentary besiegers to offer Lady Mary the chance of escape. However, having defended her family home bravely for three years, Lady Mary refused. However, there is the possibility that when Corfe finally surrendered, Lady Mary Bankes was not there at all.