Looking at what the NHL (National Hockey League) has become in today's world, it's hard to imagine that the league itself started as basically a contingency plan for a failed league with six teams. The NHL was born from the ashes of the NHA (National Hockey Association), which housed six operating teams at the time of their ceasing of operations: Montreal Canadiens, Montreal Wanderers, Ottawa Senators, Quebec Bulldogs, Toronto Blueshirts, and the Toronto 228th Battalion.
Disbanding of the NHA
Come halfway through the NHA's 1916-17 season, the 228th Battalion was called away to fight in World War I, and had to drop out halfway through the year; the NHA was suddenly a 5-team league. Adding to that the fact that Canada's Compulsory Service Act was just passed as well, requiring enlistment for all males ages 25 – 35, they then decided to suspend operations.
— NHL Public Relations (@PR_NHL) November 26, 2017
The NHL rises from the ashes
They weren't done yet, though. That Autumn, November 24, 1917, the directors for the NHA, (George Kendall of the Montreal Canadiens, Sam Lichtenhein of the Montreal Wanderers, Tom Gorman for the Ottawa Senators, M.J. Quinn of Quebec, and Frank Calder, the NHA secretary-treasurer), met at the Windsor Hotel in Montreal for three days of meetings. It was Gorman who proposed “that the Canadiens, Wanderers, Ottawa and Quebec Hockey Clubs unite to comprise the National Hockey League.” On November 26, 1917, the motion was passed, and the league was formed.
Quebec ended up unable to ice a team for the inaugural 1917-1918 NHL season, so their operations were suspended until the 1919-20 season. The Toronto Arena Company was granted a franchise to keep the NHL at 4 teams. Frank Calder was elected president and secretary-treasurer of the NHL, with an annual salary of $800. He presided over the NHL from his election in 1917 until his passing in 1943. He presided over the NHL's expansion from Canada into the United States, and had two trophies named in his honor: the Calder Memorial Trophy, awarded to the top rookie at the NHL level, and the Calder Cup, the AHL-equivalent to the Stanley Cup, awarded to the championship winning team.
Toronto would go on to win the NHL's very first championship, and won the right to play the champion of the Pacific Coast Hockey Association for the Stanley Cup. They beat the Vancouver Millionaires in a five-game Final to take home their very first NHL Stanley Cup.
From a humble 4-team start, with 26 games in a season, to the current 31-team, 82-game league that we know today, the game of professional hockey has come a long way in Canada and the U.S. The formation and continuation of the NHL raised the bar for the game of hockey, and continues to do so to this day.