The history of the Regiment goes back to 1685 when the Earl of Arran, 4th Duke of Hamilton KG. KT was granted a Commission as Colonel and raised The 6th Horse which became the 4th (Royal Irish) Dragoon Guards.
In December 1688 the victorious Prince William (he was not proclaimed King William 111 until the following February) issued a warrant for the formation of new Regiments one of which was The 10th Horse raised by Colonel William Cavendish, 1st Duke of Devonshire, KG. which became the 7th Dragoon Guards (Princess Royal’s)
In India on 22nd October 1922 the two Regiments were amalgamated to become the 4th/7th Dragoon Guards and then in 1936 the status of Royal was conferred for the Regiment to become the 4th/7th Royal Dragoon Guards
On 1st August 1992 the Regiment was amalgamated with the 5th Royal Inniskilling Dragoon Guards to form the Royal Dragoon Guards.