Letter written by Charles Darwin

14th February 1877, a thank-you note greetings on his 68th birthday two days after his birthday

“Dear Sir

I request that you will be so good as to return to the Members of your
Anthropological Society my most sincere thanks for their congratulations
on my birth-day, just received by telegram. I can assure you that I feel
very deeply the honour thus conferred on me.

Yours Faithfully,

Charles Darwin”