31st March

On this day in 1952, Alan Turing was charged with homosexual acts, offering no defence other than that he saw nothing wrong in his actions. Found guilty, he was given the alternatives of prison or oestrogen injections for a year. He accepted the latter and returned to a wide range of academic pursuits.
See THIS LINK.

The postage stamp of one of today's mathematicians at THIS LINK was issued in 1937.