LONDON (AP) — Britain marked Queen Elizabeth II's 91st birthday on Friday with gun salutes, as the monarch celebrated quietly at home.

A troop of the Royal Horse Artillery rode horse-and-gun carriages past Buckingham Palace before staging a 41-gun salute in Hyde Park at noon (1100GMT.)

Outside the palace, a band of guardsmen in scarlet tunics and bearskin hats played "Happy Birthday" during the Changing of the Guard ceremony.

There was a second salute with 62 guns at the centuries-old Tower of London.

The queen is Britain's oldest and longest-reigning monarch, having become queen on Feb. 6, 1952. She is also the world's longest-reigning living monarch since the death of Thailand's King Bhumibol Adulyadej last year.

The queen usually spends her birthday privately. She also has an official birthday, marked in June — when the weather is better — with the "Trooping the Color" military parade.