National Hockey Association

The National Hockey Association (NHA), initially the National Hockey Association of Canada Limited, was a professional ice hockey organization with teams in Ontario and Quebec, Canada. It is the direct predecessor of today's National Hockey League (NHL), and many of the business processes of the NHL today are based on the NHA. Founded in 1909 by Ambrose O'Brien, the NHA introduced six-man hockey by removing the rover position in 1911.

Source: Wikipedia — National Hockey Association (CC BY-SA 4.0)