LONDON -- Britain is marking Queen Elizabeth II’s 91st birthday with gun salutes, as the monarch celebrates quietly at home.

The royals have been sharing photos of the queen to mark the occasion on their social media profiles.

To mark The Queen's 91st birthday, we are sharing this photo from 1952 of Her Majesty and The Prince of Wales. #HappyBirthdayHerMajesty pic.twitter.com/ednBFygYue — Clarence House (@ClarenceHouse) April 21, 2017

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, UK time. There was also a 62-gun salute at the Tower of London an hour later.

Members of the King’s Troop Royal Horse Artillery First World war era fire 13-pounder field guns as part of a 41 gun salute in Hyde Park to mark Britain’s Queen Elizabeth II ‘s 91st birthday, in London, Friday, April 21, 2017. Alastair Grant, AP

Princess Elizabeth Alexandra Mary was born at 2:40am on April 21, 1926. She is Britain’s oldest and longest-reigning monarch, having become queen on Feb. 8, 1952. She is also the world’s longest-reigning living monarch since the death of Thailand’s King Bhumibol Adulyadej last year.

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On February 6, the queen became the first British monarch to reign for 65 year, celebrating her Sapphire Jubilee.

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.