George Patton competed in the 1912 pentathlon.
He didn’t win anything.
Baby doctor Benjamin Spock competed in the 1924 rowing competitions. He didn’t win anything, either.
Alfred C. Gilbert, inventor of Erector Sets, co-won the 1908 gold medal in pole vaulting.
In A.D. 66, Emperor Nero competed in the chariot races.
Since he had unlimited power and a nasty temper, the other contestants wisely let him win.
Princess Anne of England was not as lucky when she competed in horse events in 1976. She lost the competition.
However, she was the only female athlete that year who was not forced to take a gender test.