These events were followed by the accession of William and Mary, the Prince and Princess of Orange, to the throne; and the first duty in which the regiment was called upon to engage under the new dynasty, was the patrolling of the public roads to prevent highway robberies, which, owing to the commotions recently experienced in society, had become very frequent. It also furnished a detachment to protect the King's herd of deer in the Forest of Dean against the depredations of organized bands of deer-stealers.

From these duties Coy's Horse were soon relieved to engage in military operations in Ireland, which country had become the theatre of intestine war. The Papists were in arms in favour of King James, who had arrived in Ireland with a body of troops from France; and, following that system of cruelty which has invariably been practised when religion has been the subject of contention, the hapless Protestants, being the weaker party, had been made to feel the full weight of Catholic vengeance. Many of the Protestants, particularly in Inniskilling and Londonderry, had taken arms. King William sent a body of troops under Duke Schomberg to their aid, and Coy's Horse embarked at Highlake, in Cheshire, in the middle of August, 1689, for the same service.

After landing at Belfast, the regiment was employed in covering the siege of Carrickfergus, and had its post in the lines before the town. This place having surrendered on the 28th of August, a detachment of the regiment, commanded by Captain Sir William Russel, escorted the garrison, consisting of two regiments of foot, "all stout fellows, but ill clothed," the first stage from the town; and such cruelties had been practised by the Papists, that, according to Story, who was an eye-witness, the troopers experienced some difficulty in preserving the Catholic soldiers from being torn to pieces by the country people, who were stimulated to revenge by the remembrance of past injuries.

The regiment afterwards advanced with the army towards Newry, where a party of the enemy was assembled, who, on the approach of the English, set fire to the town, and retreated over the mountains to Dundalk. The English passed the mountains on the following day, when the enemy quitted Dundalk and retired to Atherdee, where the main body of King James's army was assembled.

Marshal Duke Schomberg, finding Dundalk to be a strong situation, with a convenient harbour for obtaining supplies from England, and knowing that the enemy's army was more than double his own in numbers, formed an intrenched camp, where he resolved to continue during the remainder of the campaign; but the ground where the troops were encamped being low, and the weather proving wet, this injudicious choice of situation proved so fatal to his army, that the infantry corps lost half their men from disease. Coy's Horse remained at Dundalk upwards of a month, and afterwards proceeded to Carlingford for the convenience of forage. During the winter, detached parties had frequent encounters with the bands of armed Papists who prowled the country, committing every description of outrage; and an out-guard of the regiment, posted in the pass of Newry, was sharply engaged with a party of the enemy, who attempted to force the pass, but were repulsed with loss, the gallant English Cuirassiers proving more than a match for their antagonists.

1690

In June, 1690, King William arrived in Ireland to command the army in person, and the regiment was now called upon to serve under the eye of its sovereign. This circumstance is said to have given rise to a laudable feeling of emulation in all ranks of the army, and the troopers longed for an opportunity to distinguish themselves in presence of their King. The desired opportunity soon occurred; the King, advancing up to the banks of the Boyne, found the enemy in position on the opposite side of the river, and the troops prepared for battle. This regiment was with His Majesty on the evening preceding the battle, while reconnoitring the enemy's position, and was exposed to a cannonade, on which occasion the King was wounded in the shoulder, and the regiment had three men and nine horses killed.

Early on the 1st of July, as the rays of morning-light shed their lustre on the camp, the English and Dutch troops appeared in motion, every man displaying a green branch in his hat; and soon the columns were seen advancing towards the Boyne, their glittering arms, waving plumes, and floating banners, exhibiting all the pomp of war: the French and Irish stood to their arms and prepared to defend their post. Coy's Horse, forming part of the cavalry of the right wing, were in the column which forded the river near Slane Bridge; some opposition was made by a regiment of Irish dragoons, which was attacked, and its commanding officer and about 70 men killed. After passing the river, the troops advanced through large corn-fields, crossed several deep ditches, and overcoming every obstacle with an ardour which bespoke the valour and confidence which glowed in every breast, the enemy's left wing was dismayed and retreated towards Duleck. Coy's Horse were amongst the squadrons which galloped forward in pursuit, and charging the Irish foot, cut them down with a great slaughter. While these events were transpiring on the right, King William passed the river with the main body of his forces: the enemy was overpowered at every point, and His Majesty stood triumphant on the field of battle. King James fled to Dublin, and afterwards to France, and was followed by the French troops; but the Irish Papists resolved to maintain his cause to the last extremity.

Coy's Horse advanced with King William to Dublin, and were afterwards with the army before Limerick, during the unsuccessful siege of that place, when His Majesty returned to England, the regiment went into quarters near Cork.

1691