Siege of Mons (1709)

Following the neutralisation of the French threat, Marlborough and Eugene directed a force under the Prince of Orange to surround the city of Mons, which was done on 19 and 20 September.^[16] The Prince's force comprised approximately 30 battalions, of which at least 14 were Dutch and 4 were British, and 33 squadrons amounting to around 10,000 soldiers.^[17][1] On the orders of Boufflers, three French battalions had successfully slipped through the Allied lines from Malplaquet to reinforce Mons.^[5] On 24 September, the Prince attacked the outer-works of the fortress. The following day, Eugene arrived at Mons with the main siege corps of the Allied army.^[12] Boufflers received orders from Louis to not risk another battle, and therefore no attempt was made by the French to relieve Mons once the siege was underway.^[5]

On the night of 26 September, a two-pronged assault on the fortress was attempted. However, many Allied soldiers became lost in the darkness. The approach was only noticed by the garrison when moonlight illuminated the scene, resulting in heavy Allied loses.^[12]

The Allies began the construction of trenches and artillery positions, but work was hampered by torrential rain and constant shelling from the defenders. Both Cadogan and Richard Molesworth were injured. On 10 October, Marlborough wrote to the Earl of Sunderland from his camp at Havré to express his frustration at the weather's impact on the siege's progress.^[18] To combat the problem, Allied troops dug ditches to drain the water into the river Trouille and reinforced the ground with fascines. The Franco-Spanish defenders attempted a sortie with 300 soldiers, who engaged a British regiment before being driven back by reinforcements.^[12] On 16 October, the Allies launched a successful but costly attack on the counterscarp at the Gate of Havre.^[19]

On 19 October, construction of the Allied artillery redoubt was completed and breaching batteries had been established.^[19] That morning the batteries began firing upon the town's defences, with great success.^[19] At noon on 20 October, observing the Allied preparations for an assault supported by artillery, Grimaldi sounded the chamade and signalled his intention to surrender.^[7] On 23 October, the Franco-Spanish accepted the Allied terms of capitulation and the garrison's remaining 1,500 men left Mons with the honours of war but without their cannon or mortars.^[20][21]

After losing Mons, the French and Spanish were forced to evacuate the area between the Sambre and Meuse rivers.^[22] The States of the County of Hainaut, with its capital in Mons, recognised Charles VI, Holy Roman Emperor as Charles III of Spain. Owing to heavy French and Allied loses at Malplaquet, the capture of Mons marked the final engagement of the 1709 campaign season in the war. The Allied armies dispersed into winter quarters until 1710.^[5]