Notwithstanding these successful diversions, Lieut.-General Burgoyne experienced great difficulties in his advance, and eventually, his troops being exhausted with fatigue and privation, his advance opposed by superior numbers, and his retreat cut off, he capitulated. The army under General Sir William Howe had better success, and captured Philadelphia. The enemy having despatched part of the force originally opposed to Lieut.-General Burgoyne, to join their army of the south under General Washington, the ROYAL FUSILIERS were sent from the vicinity of New York to reinforce the army in Pennsylvania, and in the early part of December they were engaged in a skirmish with the Americans in front of Philadelphia; but only lost one man. [Sidenote: 1778] Louis XVI. having acknowledged the independence of the revolted British States in America, and concluded a treaty of alliance with them, Great Britain declared war against France; and as the French had agreed to assist the Americans, a concentration of the British forces was deemed advisable. The army accordingly retired in June, 1778, from Philadelphia, and crossed the Delaware, and proceeded through the Jerseys, from whence it embarked for New York. Numerous obstacles had to be overcome in this retreat, and the troops suffered much from the excessive heat of the weather: some sharp skirmishing also took place, but the ROYAL FUSILIERS do not appear to have sustained any loss. [Sidenote: 1779] The regiment remained at the lines near New York until the summer of 1779, when it was employed in an expedition commanded by Major-General Tyron, sent into East Sound with a view of drawing General Washington from the strong post which he occupied in the mountains into Connecticut for the defence of the towns on that coast. The fleet arrived at the harbour of _Newhaven_ on the 5th of July, and the first division of the Army, which consisted of the flank companies of the guards, ROYAL FUSILIERS, fifty-fourth regiment, and a detachment of Jagars, with four field-pieces, under Brigadier-General Garth, landed about five o'clock in the morning a mile south of the town, and advanced, making a circuit of seven miles to gain the head of the creek on the western side of the place. Some skirmishing occurred on the march, but the King's troops overcame all opposition and took possession of the town: at the same time the second division landed and took post at Rock Fort. On the following day the troops destroyed all the public stores, and part of the ordnance, with a number of vessels, and afterwards re-embarked, bringing off six field-pieces and an armed privateer. On the 7th of July the fleet anchored off the village of _Fairfield_; the British troops landed and defeated a party of Americans; the enemy kept firing from windows and the tops of houses, which provoked a band of loyal emigrants to set the place on fire, by which the town and a number of boats were destroyed.