Box lacrosse The roots of indoor lacrosse are obscure, but its invention has been attributed to one Paddy Brennan, a field lacrosse player and referee from Montreal, who, being annoyed by the constant slowing of play from balls going out of bounds in the field game, experimented with indoor games at the Mount Royal Arena during the early 1920s. Joseph Cattarinich and Leo Dandurand, owners of the National Hockey League's Montreal Canadiens in the 1920s, led the participating ice hockey arena owners to introduce the new sport. In the 1930s, 6 v 6 indoor lacrosse came to be played in the summer
Box lacrosse in unused hockey rinks. Canadians adopted the new version of the sport quickly. Eventually, it became the more popular version of the sport in Canada, supplanting field lacrosse. The form was also adopted as the primary version of the game played on Native American reservations in the US and Canada by Iroquois and other Native peoples. It is the only sport in which the American indigenous people are sanctioned to compete internationally, participating as the Iroquois Nationals. However, many field lacrosse enthusiasts viewed the new version of the sport with negativity. The first professional box lacrosse games were held in