The Siege of Drogheda was a significant military engagement during the Cromwellian conquest of Ireland. Following years of conflict stemming from religious and political grievances, Oliver Cromwell, representing the Parliamentarians, sought to solidify control over Ireland. Drogheda, held by Royalist forces loyal to King Charles I, was strategically important. The siege commenced on September 3, 1649, and lasted until September 11, during which Parliamentarian forces conducted intense artillery bombardments and assaults. The town's defenses, which included high walls and fortified positions, ultimately succumbed to Cromwell's determined onslaught.

The siege ended with Cromwell ordering his troops to storm the town after nearly a week of siege. Upon capturing Drogheda, the Parliamentarian forces faced the garrison and defenders, leading to a notorious conclusion where many were executed. The ruthless nature of this siege demonstrated Cromwell's commitment to suppressing Royalist resistance and sent a strong message to other towns in Ireland regarding the consequences of defiance. Reports of atrocities committed during the siege have remained contentious, contributing to Cromwell's controversial legacy.

This event was part of Cromwell's larger campaign to establish English control over Ireland following the Irish Confederate Wars. The successful capture of Drogheda paved the way for further territorial gains by the Parliamentarian forces, influencing the political landscape of Ireland and contributing to the eventual establishment of the Protectorate. The siege, while tactical in success, was marked by grim surrender terms for the defenders, further embroiling Cromwell's name in debates about military ethics and governance.