Cromwell arrived at Drogheda on 3 September and his siege guns, brought up by sea, arrived two days later. His total force was about 12,000 men and eleven heavy, 48-pounder, siege artillery pieces. Drogheda's defences consisted of medieval
curtain walls. These were high but relatively thin, making them vulnerable to cannon fire. Most of the town was situated on the northern bank of the River Boyne, but its two main gates the Dublin and Duleek gates, were south of the river along with the
Millmount Fort that overlooked the defences. Cromwell positioned his forces on the south side of the River Boyne in order to concentrate them for the assault, leaving the northern side of the town open and covered by a small screen of cavalry. A squadron of Parliamentarian ships also blockaded the harbour of the town. In a letter to
William Lenthall,
Speaker of the
English House of Commons, written shortly after the storming of the town, Cromwell explained why he did not fully
invest the town, an action that would have left his divided command vulnerable to an attack by a relieving force and a simultaneous
sortie by the garrison, but rather concentrated his troops on the south side of Drogheda for a swift assault.
Summons to surrender The Parliamentary commander set up his batteries at two points near the Duleek gate, on either side of St Mary's church (on the site of the current Gerrard's Church), south west of, and near the
Millmount Fort, where they would have an interlocking field of fire. Having opened two breaches in the walls, one to the south and the other to the east of the church, he called on the Royalists to surrender. On Monday, 10 September, Cromwell had a letter delivered to Sir Arthur Aston, which read: The contemporary laws of war were clear: if surrender was refused and a garrison was taken by assault, then its defenders could lawfully be killed. That is; acceptance of a surrender of the besieged after the storming of the breach was at the
discretion of the attacker. Aston refused to surrender even though the garrison of Drogheda was critically short of gunpowder and ammunition. Their hope was that Ormonde, nearby at Tercroghan with some 4,000 Royalist troops, would come to their relief.
Assault At 5:00 PM, on 11 September, Cromwell ordered simultaneous assaults on the southern and eastern breaches in the walls of Drogheda. Three regiments attacked the breaches, gaining a foothold in the south but being beaten back in the east. Cromwell had to reinforce the eastern attack with two more regiments before it succeeded, the second wave climbing over "a heaped pile of their comrades' corpses." At the southern breach, the defenders counterattacked. The death of their commander, Colonel Wall, caused them to fall back, allowing further Parliamentary reinforcements to be funnelled into the breach. In the fighting at the walls some 150 Parliamentarian troops, including Colonel Castle, were killed. After the death of Colonel Wall with more and more Parliamentary soldiers streaming into the breaches, the Royalist resistance at the walls collapsed. The surviving defenders tried to flee across the River Boyne into the northern part of the town while Aston and 250 others took refuge in
Millmount Fort overlooking Drogheda's southern defences. Others remained stranded in the towers along the town walls, while Cromwell's troops surged into the town below them. With up to 6,000 Parliamentary troops now inside the town, Drogheda had been taken. ==Massacre==