1937 - The Title of Duke of Windsor, granted to the former King Edward VIII, was formalized by Letters Patent. This, however, was not published in the London Gazette. On 27 May 1937, another letters patent was issued to confer the style of HRH to the Duke of Windsor and to exclude his wife and any possible descendants from holding the style of HRH. This was published in the London Gazette. I always thought the original issued today in 1937 may have been a normal Letter Patent that included “heirs male of his body” and would have allowed the then Wallis Simpson (the couple married in June 1937) to have the HRH. This Letter Patent was amended over the next couple of months and reissued in May 1937.

https://www.thegazette.co.uk/London/issue/34402/page/3429/data.pdf