master of the horse
Noun
Meaning
(historical) The Ancient Roman Magister Equitum, an official appointed by the dictator to act next under himself.
(historical) An equerry, especially the exalted official bearing this name at the British court.
Source: en.wiktionary.orgExamples
David, 2000, pg 246 Caesar's Master of the Horse Marcus Aemilius Lepidus marched over 6,000 troops into Rome on 16 March to restore order and to act as the bodyguards of the Caesarian faction.
He was also titled "magister equitum et peditum" ("Master of the Horse and of Foot"), placing him in charge of both the cavalry and infantry forces of the Western Roman Empire.
On his return in 1481, when Prince John was crowned as King John II, Afonso was made Master of the Horse for his distinguished exploits, chief equerry (estribeiro-mor) to the King, a post which he held throughout John's reign (1481–95).
When a Dictator entered office, he appointed to serve as his second-in-command a magister equitum, the Master of the Horse, whose office ceased to exist once the Dictator left office.
However, it might also include individuals who were not members of Parliament such as household officers (e.g. the Master of the Horse) and members of the royal family.