When the attempts made by King James to establish papacy and arbitrary government had alarmed his subjects, and the Prince of Orange was preparing an armament for the invasion of England, the regiment was one of the corps which marched from Scotland to support the authority of the King; and in the early part of November, 1688, it arrived in the vicinity of London, when it was ordered to occupy quarters in Spitalfields and the Tower Hamlets. The Prince of Orange landed on the 5th of November; King James discovered that he had alienated the affections of his subjects, both civil and military, and he fled to France. Colonel BUCHAN'S regiment was ordered, by the Prince of Orange, to occupy quarters at Witney, in Oxfordshire. [Sidenote: 1689] The Prince and Princess of Orange were elevated to the Throne by the titles of King William and Queen Mary; and Colonel Buchan having adhered to the interests of King James, King William conferred the colonelcy of the regiment on Colonel Francis Fergus O'Farrell, by commission dated the 1st of March, 1689. From Oxfordshire, the regiment marched to Gravesend, where it embarked for Holland, and joining the Dutch army commanded by Prince Waldeck, served the campaign of that year with the division under the Earl (afterwards Duke) of Marlborough. The regiment took part in a sharp action with the French troops, commanded by Marshal d'Humières, at _Walcourt_, in the province of Namur, on the 25th of August, on which occasion the French were repulsed in their attacks on the allied army, with considerable loss. [Sidenote: 1690] The regiment passed the winter in Flanders, and in the summer of 1690 again took the field; it was on its march for Brussels on the 21st of June, in order to join the allied army; but Prince Waldeck engaged the French at Fleurus, without waiting for the arrival of the British troops, and was defeated. This disaster occasioned the services of the army to be limited to defensive operations during the remainder of the campaign. [Sidenote: 1691] In March, 1691, the regiment was encamped at Halle, in South Brabant, and formed in brigade with the second battalion of the Royals; the French besieged Mons, and the allies were too few in numbers to prevent the capture of the place by the enemy. After the surrender of Mons, the regiment was placed in quarters until May, when it encamped near Brussels, and was formed in brigade with the Royals, and the Scots regiments of Mackay, Ramsay, and Angus, under the orders of Brigadier-General Ramsay. In a list of the army in Flanders, printed in July, 1691, the regiment is styled "O'FARRELL'S FUSILIERS;" and its uniform is stated to be _red, faced and lined with the same colour_. At the termination of the campaign, the regiment was again placed in winter-quarters. [Sidenote: 1692]