May 21
1881 — A small group of tennis club members meets at the Fifth Avenue Hotel in New York City to form the world's first national governing body for tennis: the United States National Lawn Tennis Association. The new organization is created to standardize tennis rules and regulations and to encourage and develop the sport.
1966 — Kauai King, the Kentucky Derby winner ridden by Don Brumfield, wins the Preakness Stakes by 1 3/4 lengths over Stupendous.
1977 — Heavily favored Seattle Slew, ridden by Jean Cruguet, wins the Preakness Stakes by 1 1/2 lengths over Iron Constitution, a 31-1 shot.
1979 — The Montreal Canadiens win their 21st Stanley Cup by beating the New York Rangers 4-1 in Game 5.