Dragoon Guards was the designation used to refer to certain heavy cavalry regiments in the British Army from the 18th century onwards.
The word dragoon originally meant mounted infantry, who were trained in horse riding as well as infantry fighting skills. However, usage altered over time and during the 18th century, dragoons evolved into conventional light cavalry units and personnel. Dragoon regiments were established in most European armies during the late 17th and early 18th centuries. The name is possibly derived from a type of firearm (called a dragon) carried by dragoons of the French Army. There is no distinction between the words dragon and dragoon in French; both are referred to as dragon.
During the Napoleonic Wars, dragoons generally assumed a cavalry role, though remaining a lighter class of mounted troops than the armored cuirassiers. Dragoons rode larger horses than the light cavalry and wielded straight, rather than curved swords.
The Royal Scots Greys was a cavalry regiment of the British Army from 1707 until 1971, when they amalgamated with the 3rd Carabiniers (Prince of Wales's Dragoon Guards) to form The Royal Scots Dragoon Guards (Carabiniers and Greys).
Before the Royal Scots Dragoons embarked for Flanders in 1694, they were reviewed by William III in Hyde Park and it is recorded that they made a fine sight, for the entire regiment rode grey horses. This is the earliest known instance of them being mounted on the horses from which their name, the ‘Scots Greys’, was derived. For almost 300 years the regiment remained mounted exclusively on grey horses.