The corps was formed as the Troop of Gentlemen in 1509 by King Henry VIII to act as a mounted escort, armed with spear and lance to protect the sovereign, in battle or elsewhere.

As the "Nearest Guard" to the Monarch, the unit attracted an aristocratic and aspiring membership, which could be utilised as a cadre of young officers when levies were raised for overseas service.

[1] Today, the duties are purely ceremonial: the Gentlemen accompany and attend the sovereign at various events and occasions, including state visits by heads of state, the opening of parliament, and ceremonies involving the various orders of chivalry, including the Order of the Garter.

The Corps today consists of five Officers (the Captain, the Lieutenant, the Standard Bearer, the Clerk of the Cheque and Adjutant and the Harbinger) and 24 Gentlemen.

It has a skirted red coatee with Garter blue velvet cuffs and facings embroidered with the Tudor royal badge of the portcullis.

Officers wear, in addition, gold aiguillettes, and carry sticks of office—gold for the Captain, silver for the Lieutenant, Standard Bearer and Clerk of the Cheque, and ivory for the Harbinger—which they receive from the Sovereign on appointment.

Next to this is the Royal Cipher of the reigning monarch, with the name of the corps ("Gentlemen at Arms") put diagonally from top to bottom.

[3] In 2009, at a celebration of the Corps' 500 years of personal service to the Sovereign, Queen Elizabeth II presented a special riband to be displayed on the Standard.