The Duke of Cumberland, grandson of George II, brother of George III, having, in April 1782, been elected Grand Master of England, it was resolved by the Grand Lodge “that whenever a prince of the blood did the Society the honor to accept the office of Grand Master, he should be at liberty to nominate any peer of the realm to be the Acting Grand Master” (Constitutions of Grand Lodge of England, edition 1784, page 341). The officer thus provided to be appointed was subsequently called in the Constitutions of the Grand Lodge of England (edition 1841), and is now called the Pro Grand Master.
In the American system, the officer who performs the duties of Grand Master in case of the removal, death, or inability of that officer, is known as the Acting Grand Master. For the regulations which prescribe the proper person to perform these duties, see Grand Master.