The Battle of the Boyne ( ) was a battle in 1690 between the forces of the deposed King James II, and those of King William III who, with his wife Queen Mary II (his cousin and James's daughter), had acceded to the Crowns of England and Scotland in 1689. The battle took place across the River Boyne close to the town of Drogheda in the Kingdom of Ireland, modern-day Republic of Ireland, and resulted in a victory for William. This turned the tide in James's failed attempt to regain the British crown and ultimately aided in ensuring the continued Protestant ascendancy in Ireland.
The battle took place on 1 July 1690 O.S. William's forces defeated James's army, which consisted mostly of raw recruits. Although the Williamite War in Ireland continued until the signing of the Treaty of Limerick in October 1691, James fled to France after the Boyne, never to return.
Background
The battle was a major encounter in James's attempt to regain the thrones of England and Scotland, resulting from the Invitation to William and William's wife, Mary, from the 'immortal seven' English peers to take the throne to defend Protestantism. But the conflict had broader and deeper European geopolitical roots, of the League of Augsburg and the Grand Alliance against the expansionist ambitions of Catholic Louis XIV of France, or of the House of Bourbon against the House of Habsburg. If the battle is seen as part of the War of the Grand Alliance, Pope Alexander VIII was an ally of William and an enemy to James; the Papal States were part of the Grand Alliance with a shared hostility to the Catholic Louis XIV of France, who at the time was attempting to establish dominance in Europe and to whom James was an ally.
The previous year William had sent the Duke of Schomberg to take charge of the Irish campaign. He was a 75-year-old professional soldier who had accompanied William during the Glorious Revolution. He brought an army of 20,000 men, which arrived at Bangor. Under his command, affairs had remained static and very little had been accomplished, partly because the English troops suffered severely from fever and the army's move south was blocked by Jacobite forces; both sides camped for the winter.
In an Irish context, the war was a sectarian and ethnic conflict, in many ways a re-run of the Irish Confederate Wars of 50 years earlier. For the Jacobites, the war was fought for Irish sovereignty, religious tolerance for Catholicism, and land ownership. The Catholic upper classes had lost or had been forced to exchange almost all their lands after Cromwell's conquest, as well as the right to hold public office, practise their religion, and sit in the Irish Parliament. To these ends, under Richard Talbot, 1st Earl of Tyrconnel, they had raised an army to restore James II after the Glorious Revolution. By 1690, they controlled all of Ireland except for Derry and Enniskillen.
The majority of Irish people were Jacobites and supported James II due to his 1687 Declaration of Indulgence or, as it is also known, the Declaration for the Liberty of Conscience, that granted religious freedom to all denominations in England and Scotland and also due to James II's promise to the Irish Parliament of an eventual right to self-determination.
Conversely, for the Williamites in Ireland, the war was about maintaining Protestant rule in Ireland. They feared for their lives and their property if James and his Catholic supporters were to rule Ireland, nor did they trust the promise of tolerance, seeing the Declaration of Indulgence as a ploy to re-establish Catholicism as the sole state religion. James had already antagonised English Protestants with his actions. In particular, they dreaded a repeat of the Irish Rebellion of 1641, which had been marked by widespread killing. For these reasons, Protestants fought en masse for William of Orange. Many Williamite troops at the Boyne, including their very effective irregular cavalry, were Ulster Protestants, who called themselves "Enniskilliners" and were referred to by contemporaries as "Scots-Irish". These "Enniskilliners" were mostly the descendants of Anglo-Scottish border reivers; large numbers of these reivers had settled around Enniskillen in County Fermanagh.