Karl Münich of Austria (born 1848) competed in men's sabre in the 1912 Olympics when he was 63 years, 11 months, 22 days old, but did not win a medal.
The oldest olympic fencing medalist is a trickier question:
Charles Newton‐Robinson of Great Britain won a silver medal, men's epee team in the 1906 Olympic Intercalated Games when he was 52, but the modern IOC doesn't recognize those every-other-year medals from Athens.
Aladár Gerevich of Hungary was 50 when he won his last gold medal in the 1960 Olympics. Arguably the greatest sabreur ever, he won ten medals starting in 1932, seven golds, a silver, and two bronzes. His son Pal won two bronzes and is a coach in Vienna.
He competed at the 1972 and 1976 Summer Olympics.
Gillian Sheen.
Jens Howe is a German fencer. He competed for East Germany at the 1988 Summer Olympics.
Ann Brannon was a British Women's fencer who competed in the 1980, 1984 and 1988 Summer Olympics.
marathon
Japan's rider Hiroshi Hoketsu at age 71 was the oldest Olympian at the London 2012 Olympics.
stinky hit
72
Thomas Jefferson
Mariel Zagunis, an American fencer, carried the American flag at the 2012 London Opening Ceremony.
85
Thorpe