The Battle of Rathmines is fought in and around what is now the Dublin suburb of Rathmines on August 2, 1649, during the Irish Confederate Wars. It is fought between an English Parliamentarian army under Michael Jones which holds Dublin and an army composed of Irish Confederate and English Royalist troops under the command of the James Butler, 1st Duke of Ormonde.
In July 1649, Ormonde, marches his coalition forces of 11,000 men to the outskirts of Dublin with the intent of taking the city from its Parliamentary garrison, which had landed there in 1647. Ormonde takes Rathfarnham Castle and camps at Palmerston Park in Rathgar, about 4 km south of the city. The area from Ormonde’s camp to the city of Dublin is now a heavily urbanised area, but in 1649, it is open countryside. Ormonde begins inching his forces closer to Dublin by taking the villages around its perimeter and to this end, sends a detachment of troops to occupy Baggotrath Castle, on the site of present-day Baggot Street bridge. For reasons which have never been clear, they take several hours to reach Baggotrath, a distance of about a mile, and they arrive to find that the Parliamentary troops have already occupied the castle.
However, Ormonde is not expecting Michael Jones, the Parliamentary commander, to take the initiative and has not drawn up his troops for battle. Unfortunately for the Royalists, this is exactly what Jones does, launching a surprise attack on August 2 from the direction of Irishtown with 5,000 men and sending Ormonde’s men at Baggotsrath reeling backwards towards their camp in confusion.
Too late, Ormonde and his commanders realise what is going on and send units into action piecemeal to try to hold up the Parliamentarian advance, so that they can form their army into battle formation. However, Jones’ cavalry simply outflanks each force sent against them, sending them too fleeing back south through the townland of Rathmines. The battle becomes a rout as scores of fleeing Royalist and Confederate soldiers are cut down by the pursuing Roundheads. The fighting finally ends when the English Royalist troops under Murrough O’Brien, 1st Earl of Inchiquin, mounts a disciplined rearguard action, allowing the rest to get away. Ormonde claims he has lost less than a thousand men. Jones claims to have killed around 4,000 Royalist or Confederate soldiers and taken 2,517 prisoners, while losing only a handful himself. Ormonde certainly loses at least one leading officer, Christopher Plunkett, 2nd Earl of Fingall, who is fatally wounded and dies in Dublin Castle a few days later. Ormonde also loses his entire artillery train and all his baggage and supplies.
In the aftermath of the battle, Ormonde withdraws his remaining troops from around Dublin, allowing Oliver Cromwell to land in the city at Ringsend with 15,000 veteran troops on August 15. Cromwell calls the battle “an astonishing mercy,” taking it as a sign that God has approved of his conquest of Ireland. Over the next four years he completes the Cromwellian conquest of Ireland.
Without Jones’ victory at Rathmines, the New Model Army would have had no port to land at in Ireland and the Cromwellian conquest of Ireland would have been much more difficult. Ormonde’s incompetent generalship at Rathmines disillusions many Irish Confederates with their alliance with the English Royalists and Ormonde is ousted as commander of the Irish forces the following year.