The Battle of the Boyne was fought in 1690 between the Catholic King James II and his nephew and son-in-law the Protestant King William of the Dutch House of Orange. In 1688, the English Parliament invited William, who was married to James’ daughter Mary, to depose James as monarch of England and Scotland. It was in Ireland however that William and James faced each other at the Battle of the Boyne, as James made his desperate attempt to regain control of the crown.

Both Kings commanded their armies in person. William had around 36,000 men and James had 25,000 – the largest number of troops ever deployed on an Irish battlefield. English, Scottish, Dutch, Danes and French Huguenots made up William’s army (Williamites), while James’ men (Jacobites) were mainly Irish Catholics, dispossessed gentry and peasants pressed into service, reinforced by 6,500 French troops sent by King Louis XIV. There were three issues at stake at the battle: The Throne of England, French Dominance of Europe and Power in Ireland.

William's camp was on the north side of the river. James’ was on the south side with the two armies facing each other. All the fighting took place on the south side of the river as the vastly outnumbered Jacobites defended their position. As folklore would have it, James provided his troops with alcohol to boost their morale - this just resulted in weakening their position further as they went to battle with hangovers and less sophisticated weaponry. Ultimately the Jacobites had to retreat. James returned to Dublin and from there he went to Cork and set sail for France, never to set foot in Ireland or England again. William triumphantly marched in to Dublin two days after the battle, where he commemorated his victory in St. Patricks Cathedral.

As the Battle of the Boyne was not decisive in any way, the war continued. Mainly thanks to William's biggest blunder – instead of opting for peace and reconciliation he lambasted the Jacobites and drew up punitive terms under which their surrender might be recognised. Winning hearts and minds obviously was not very high on his agenda and thus he actually managed to stiffen the enemy’s resistance which only ended more than a year later at Limerick.

The defeat of James' ill prepared Catholic army resulted in securing William’s Protestant hold over not only England and Scotland but also of Ireland. This battle is therefore regarded as central in the struggle between the Irish Protestant and Catholic communities as it protected the dominance of Protestant interests in Ireland for centuries to come. It could be seen as the beginning of the religious sectarian struggle which waged on to modern times.

The Battle of the Boyne became a key part of Irish Protestant tradition and to this day is still commemorated in Northern Ireland by the Orange Order each 12th of July.