The 1st (His Majesty's Own) Troop of Horse Guards was formed from King Charles II's exiled followers in the Netherlands (the Stuart monarchs had been overthrown during the English Civil War, and replaced with the Commonwealth).
The regiment was formed in 1658, and placed on the English establishment three years later, with the official formation of the "modern" British Army. It fought at Dettingen, along with four other troops of the Royal Horse Guards, and eventually absorbed the 3rd Troop of Horse Guards and the 1st Troop, Horse Grenadier Guards. On 25 June 1788, the regiment became the 1st Regiment of Life Guards.