In any case, Her Majesty would have been a middle-aged woman of 46 at her accession, in which case she -- like her Danish counterpart, who also succeeded in 1972 -- would be celebrating only her golden jubilee this year.
But Elizabeth's immediate predecessor did not abdicate. Not relevant at all.
If you're going to place this against the Sun king, on the basis of his accession to the throne as a minor, then you might as well place one against the current British queen, on the basis that she would not have succeeded early, had not her uncle (King Edward VIII) abdicated.
If a regency can place an asterisk on a monarch's reign, then why not the abdication of the predecessor?
Hugo Vickers argues that, because the beginning of Louis's reign was a regency, the Queen is actually already the world's longest-reigning monarch. https://www.tatler.com/article/why-the-queen-is-technically-the-worlds-longest-reigning-monarch?utm_medium=Social&utm_campaign=SocialFlow&utm_source=Twitter
This would actually happen on 26 May 2024 when Her Majesty’s reign would be 26,408 days to Louis XIV’s 26,407.
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