(a) Queen’s Birthday
HRH’s birthday is April 21 (when she turned 95) but is celebrated with Trooping the Colour (of course saw when I was living in London) on the second Saturday in June (b/c better weather).
The ceremony of Trooping the Colour is believed to have been performed first during the reign of King Charles II (1660 – 1685). In 1748, it was decided that this parade would be used to mark the official birthday of the Sovereign and it became an annual event after George III became King in 1760.
Origins of Trooping the Colour – Trooping the Colour
https://www.householddivision.org.uk/trooping-the-colour-origins
Trooping the Colour: Queen celebrates her birthday with scaled-back ceremony at Windsor Castle
187,478 views • Jun 12, 2021
[1:04] https://www.youtube.com/watch?v=LSLCGgW4J_0
(b) Prince Philip’s 100th Birthday
Queen Elizabeth gifted rose as royals remember Prince Philip
8,396 views • Jun 10, 2021