1747-1847-1947 and 1754-1854-1954

The Broadway 1947 original production had a 1747-1847-1947 time sequence. In the 1954 film the sequence changed to 1754-1854-1954. In 1947 the King of the UK (and theoretically of Brigadoon as well) was George VI, but in 1954 the Queen was his daughter Elizabeth II. In the subsequent Broadway productions and the US television version, the time sequence started in 1757, 1763, 1766 and 1780, and in the final—as far as I know— West End production, the sequence began in 1788, when King George III had already lost the Thirteen Colonies...

The dwellers of Brigadoon couldn't care less about all this, of course, it's just trivia. But Fiona Campbell (Cyd Charisse), who was a young lady in 1754... would already be a grandmother in 1788!