The first national competitions occurred in England, Canada, the U.S., and Austria during the 1930s. The first international ice dance competition took place as a special event at the World Championships in 1950 in London. British ice dance teams dominated the sport throughout the 1950s and 1960s, then Soviet teams up until the 1990s. Ice dance was formally added to the 1952 World Figure Skating Championships; it became an Olympic sport in 1976. In the 1980s and 1990s, there was an attempt by ice dancers, their coaches, and choreographers to move ice dance away from its ballroom origins to more theatrical performances. The ISU pushed back by tightening rules and definitions of ice dance to emphasize its connection to ballroom dancing. In the late 1990s and early 2000s, ice dance lost much of its integrity as a sport after a series of judging scandals, which also affected the other figure skating disciplines. There were calls to suspend the sport for a year to deal with the dispute, which seemed to impact ice dance teams from North America the most. Teams from North America began to dominate the sport starting in the early 2000s.