Early games used an inflated rubber ball that came from India known as a "pulu" (the single Indian word for all "balls"). Pronounced "polo" by the English, both the game and the ball became known as "water polo."

To attract more spectators to swimming exhibitions, the London Swimming Association designed a set of water polo rules for indoor swimming pools in 1870.

At first, players scored by planting the ball on the end of the pool with both hands. A favorite trick of the players was to place the five-to-nine inch rubber ball inside their swimming suit and dive under the murky water,they would then appear again as close to the goal as possible.

The introduction of the "Trudgeon stroke" by Scottish players changed the nature of water polo. It became a game that emphasized swimming, speed and passing. Scottish rules moved from a rugby variant to a soccer style of play. Goals became a cage of l0 x 3 feet and a goal could be scored by being thrown. Players could only be tackled when they "held" the ball and the ball could no longer be taken under water. The small rubber ball was replaced by a leather soccer ball.

If the player came up too near the goal, he was promptly jumped on by the goalie, who was permitted to stand on the pool deck. Games were often nothing more than gang fights in the water as players ignored the ball, preferring underwater wrestling matches that usually ended with one man floating to the surface unconscious.

Water polo was first played in the USA in 1888. The game featured the old rugby style of play which resembled American football in the water. The influence of football made the American version of water polo even rougher than the English version. "American style" water polo became very popular and by the late 1890's was played in such venues as Madison Square Garden and Boston's Mechanics Hall, attracting 14,000 spectators to national championship games.

The game of the day featured plays like the "flying salmon," where the player with the ball leapt through the air from the backs of his teammates to score a goal. Violence was the game's main attraction.

Meanwhile, the rest of the world adopted the Scottish rules: Hungary in 1889, Belgium in 1900, Austria and Germany in 1894 and France in 1895. By 1900, water polo was so popular it became the first team sport added to the Olympic program.

At the 1904 Olympics in St. Louis, only U.S. club teams were willing to compete under American rules and in horrid conditions. The New York Herald newspaper reported several athletes were stricken with typhoid fever after competing in an artificial, contaminated pond. "The water was green and slimy, like stagnant putrid pools found in swamps. After the first day's competition, seven of twelve NYAC men were compelled to take to bed, sick from the effects of the water in which they swam," reported the Herald. The New York Athletic Club defeated the Chicago Athletic Association for the gold medal.

In 1911, the Federation International de Natation Amateur (FINA), the international governing body for all amateur aquatic sports, adopted the Scottish rules for all international events.

Women played water polo early in the century, but during the 1920s most physical educators decided that the sport was too rough for women and it was dropped by swimming clubs and colleges. It was revived in the late 1950s. Women participated for the first time in the Olympics in 2000.

Internationally, European teams have dominated the sport. The United States is the only non-European team to win Olympic medals. In addition to the gold won by the NYAC in 1904, the U.S. won silver medals in 1984 and 1988 and bronze medals in 1924, 1932 and 1972.