List of monarchs in Britain by length of reign

On 6 February 2022, Elizabeth II became the first British monarch to reign for 70 years, and large-scale celebrations for her Platinum Jubilee occurred on 2 to 5 June.

Its rulers were often acclaimed as "King of the Britons," symbolizing their influence over other Welsh territories and their resistance to external threats.

Gwynedd faced repeated challenges, including civil wars, Saxon incursions, and Norman invasions, which gradually eroded its dominance.

Gwynedd’s heartland was the mountainous region of Snowdonia, which provided natural defenses and contributed to its resilience against invaders.

The kingdom played a central role in preserving Welsh identity, language, and culture during a period of significant upheaval in Britain.

Elizabeth II delivering a speech at the official opening of the Borders Railway , on the day she became the longest-reigning British monarch.
Henry III was the longest-reigning monarch of an independent England.