The Regiment originates from the two King's Royal Regiments of Guards raised by Charles II - one in 1656 whilst in exile, the other shortly after the Restoration.
The Regiment raised by the King while abroad in Flanders was composed of a band of English Royalists and, on its formation at Bruges, was commanded by Thomas, Lord Wentworth. It was present with the Spanish Army throughout the campaign of 1657 against the French and in 1658 distinguished itself greatly at the 'Battle of the Downs'.
The remains of the Regiment continued in Flanders until the Restoration, shortly after which they were sent to Dunkirk where Lord Wentworth, in 1660, received a second commission from the King as their Colonel. They continued doing garrison duty until the sale of Dunkirk in 1662, when Charles II brought his 'Royal Regiment of Guards' to England.
Meanwhile, in 1660, the King had issued a commission to Colonel Charles Russell to raise another regiment of Royalists, which he called 'His own Royal Regiment of Guards'. The first captains in this regiment were old Cavaliers who had received commissions from Charles I to raise regiments during the Civil War.
On the death of Lord Wentworth in 1665 the two regiments were amalgamated thereby constituting one regiment of 24 companies under Colonel Russell.
Extract from the London Gazette of 29th July 1815:
"His Royal Highness has been pleased to approve of the First Regiment of Foot Guards being made a Regiment of Grenadiers, and styled 'The First or Grenadier Regiment of Foot Guards' in commemoration of their having defeated the Grenadiers of the French Imperial Guards upon this memorable occasion, the Battle of Waterloo."
The Grenadier Guards is the only regiment in the Army that has directly gained its title from the part it played in action.