history

Challenge Cup era
During the challenge cup period, none of the leagues that played for the trophy had a formal playoff system to decide their respective champions; whichever team finished in first place after the regular season won the league title. However, in 1894, four teams out of the five-team AHAC tied for the championship with records of 5–3–0. The AHAC had no tie-breaking system. After extensive negotiations and Quebec's withdrawal from the championship competition, it was decided that a three-team tournament would take place in Montreal, with the Ottawa team receiving a to the Final because they were the only road team. On March 17, in the first ever Stanley Cup playoff game, the Montreal Hockey Club (Montreal HC) defeated the Montreal Victorias, 3–2. Five days later, in the first Stanley Cup Final game, Montreal HC beat the Ottawa Hockey Club 3–1
The first Stanley Cup
In 1895, Queen's University was the first official challenger for the Cup, although it was controversial. The Montreal Victoriahad won the league title and thus the Stanley Cup, but the challenge match was between the previous year's champion, Montreal HC, and the university squad. The trustees decided that if the Montreal HC won the challenge match, the Victorias would become the Stanley Cup champions. The Montreal HC won the match 5–1 and their cross-town rivals were crowned the champions. The first successful challenge to the Cup came the next year by the Winnipeg Victorias, the champions of the Manitoba Hockey League. On February 14, 1896, the Winnipeg squad defeated the champions 2–0 and became the first team outside the AHAC to win the Cup.
As the prestige of winning the Cup grew, so did the need to attract top players. Only nine months after winning the Cup, in March 1906, the Montreal Wanderers pushed through a resolution at the annual meeting of the Eastern Canada Amateur Hockey Association (ECAHA) that would allow professional players to play alongside amateurs. Because the ECAHA was the top hockey league in Canada at the time, the Cup trustees agreed to open the challenges to professional teams. The first professional competition came one month later during the Wanderers' two-game, total goals challenge series, which they won 17 goals to 5.
The smallest municipality to produce a Stanley Cup champion team is Kenora, Ontario; the town had a population of about 4,000 when the Kenora Thistles captured the Cup in January 1907.[20] Aided by future Hall of Famers Art Ross and "Bad" Joe Hall, the Thistles defeated the Montreal Wanderers in a two-game, total goals challenge series. The Thistles successfully defended the Cup once, against a team from Brandon, Manitoba. In March 1907, the Wanderers challenged the Thistles to a rematch. Despite an improved lineup, the Thistles lost the Cup to Montreal.
In 1908, the Allan Cup was introduced as the trophy for Canada's amateurs, and the Stanley Cup started to become a symbol of professional hockey supremacy. In that same year, the first all-professional team, the Toronto Trolley Leaguers from the newly created Ontario Professional Hockey League (OPHL), competed for the Cup. One year later, the Montreal HC and the Montreal Victorias, the two remaining amateur teams, left the ECAHA, and the ECAHA dropped "Amateur" from their name to become a professional league. In 1910, the National Hockey Association (NHA) was formed. The NHA soon proved it was the best in Canada, as it kept the Cup for the next four years.
Prior to 1912, challenges could take place at any time, given the appropriate rink conditions, and it was common for teams to defend the Cup numerous times during the year. In 1912, Cup trustees declared that it was only to be defended at the end of the champion team's regular season.
Organized interleague competition
In 1914, the Victoria Aristocrats from the Pacific Coast Hockey Association (PCHA) challenged the NHA and Cup champion Toronto Blueshirts. A controversy erupted when a letter arrived from the Stanley Cup trustees on March 17, that the trustees would not let the Stanley Cup travel west, as they did not consider Victoria a proper challenger because they had not formally notified the trustees. However, on March 18, Trustee William Foran stated that it was a misunderstanding. PCHA president Frank Patrick had not filed a challenge, because he had expected Emmett Quinn of the NHA to make all of the arrangements in his role as hockey commissioner, whereas the trustees thought they were being deliberately ignored. In any case, all arrangements had been ironed out and the Victoria challenge was accepted.
Several days later, trustee William Foran wrote to NHA president Emmett Quinn that the trustees are "perfectly satisfied to allow the representatives of the three pro leagues (NHA, PCHA and Maritime) to make all arrangements each season as to the series of matches to be played for the Cup." One year later, the NHA and the PCHA concluded a gentlemen's agreement in which their respective champions would face each other for the Cup, similar to baseball's World Series, which is played between the American League and National League champions. Under the new proposal, the Stanley Cup Final series alternated between the East and the West each year, with alternating games played according to NHA and PCHA rules. The Cup trustees agreed to this new arrangement, because after the Allan Cup became the highest prize for amateur hockey teams in Canada, the trustees had become dependent on the top two professional leagues to bolster the prominence of the trophy. The PCHA's Vancouver Millionaires won the first "formal" PCHA-NHA Cup Final, three games to zero in a best-of-five series.
After the Portland Rosebuds, an American-based team, joined the PCHA in 1914, the trustees issued a statement that the Cup was no longer for the best team in Canada, but now for the best team in the world. Two years later, the Rosebuds became the first American team to play in the Stanley Cup Final. In 1917, the Seattle Metropolitans became the first American team to win the Cup. After that season, the NHA dissolved, and the National Hockey League (NHL) took its place.
In 1919, the Spanish influenza epidemic forced the Montreal Canadiens and the Seattle Metropolitans to cancel their series, marking the first time the Stanley Cup was not awarded. The series was tied at 2–2–1, but the final game was never played because Montreal Manager George Kennedy and players Joe Hall, Billy Coutu, Jack McDonald, and Newsy Lalonde were hospitalized with influenza. Hall died four days after the cancelled game, and the series was abandoned.
The format for the Stanley Cup Final changed in 1922, with the creation of the Western Canada Hockey League (WCHL). Three leagues competed for the Cup: two league champions faced each other for the right to challenge the third champion in the final series. This lasted three seasons as the PCHA and the WCHL later merged to form the Western Hockey League (WHL) in 1925. After winning in the 1924–25 season, the Victoria Cougars became the last team outside the NHL to win the Stanley Cup.
NHL takes over
Syl Apps, with the Cup before it was redesigned, in the 1940s
The WHL folded in 1926, leaving the NHL as the only league left competing for the Cup. Other leagues and clubs occasionally issued challenges, but from that year forward, no non-NHL team has played for it, leading it to become the de facto championship trophy of the NHL. In 1947, the NHL reached an agreement with trustees P.D. Ross and Cooper Smeaton to grant control of the Cup to the NHL, allowing the league to reject challenges from other leagues that may have wished to play for the Cup.
 to time the conditions for competition of the Stanley Cup, including the qualifications oThe Trustees hereby delegate to the League full authority to determine and amend from timf challengers, the appointment of officials, the apportionment and distribution of all gate receipts, provided always that the winners of this trophy shall be the acknowledged World's Professional Hockey Champions.
1.      The Trustees agree that during the currency of this agreement they will not acknowledge or accept any challenge for the Stanley Cup unless such a challenge is in conformity with the condition specified in paragraph one (1) thereof.
2.      The League undertakes the responsibility for the care and safe custody of the Stanley Cup including all necessary repairs and alterations to the cup and sub-structure as may be required from time to time, and further undertakes to insure the Stanley Cup for its full insurable value.
3.      The League hereby acknowledges itself to be bound to the Trustees in the sum of One Thousand Dollars, which bond is conditioned upon the safe return of the Stanley Cup to the Trustees in accordance with the terms of this Agreement, and it is agreed that the League shall have the right to return the trophy to the Trustees at any time.
4.      This agreement shall remain in force so long as the League continues to be the world's leading professional hockey league as determined by its playing caliber, and in the event of dissolution or other termination of the National Hockey League, the Stanley Cup shall revert to the custody of the trustees.
5.      In the event of default in the appointment of a new trustee by the surviving trustee, the "Trustees" hereby delegate and appoint the Governors of the International Hockey Hall of Fame in Kingston, Ontario, to name two Canadian trustees to carry on under the terms of the original trust, and in conformity with this Agreement.
And it is further mutually agreed that any disputes arising as to the interpretation of this Agreement or the facts upon which such interpretation is made, shall be settled by an Arbitration Board of three, one member to be appointed by each of the parties, and the third to be selected by the two appointees. The decision of the Arbitration Board shall be final.
This agreement was amended on November 22, 1961, substituting the Governors of the International Hockey Hall of Fame in Kingston, Ontario with the Committee of the Hockey Hall of Fame in Toronto, Ontario as the group that would name the two Canadian trustees, if need be. In the 1970s, the World Hockey Association sought to challenge for the Cup. The Trustees denied them the opportunity to do so.
The Cup was awarded every year until 2005, when a labour dispute between the NHL's owners and the NHL Players Association (the union that represents the players) led to the cancellation of the 2004–05 season. As a result, no Cup champion was crowned for the first time since the flu pandemic in 1919. The lockout was controversial among many fans, who questioned whether the NHL had exclusive control over the Cup. A website known as freestanley.com (since closed) was launched, asking fans to write to the Cup trustees and urge them to return to the original Challenge Cup format. Adrienne Clarkson, then Governor General of Canada, alternately proposed that the Cup be presented to the top women's hockey team in lieu of the NHL season. This idea was so unpopular that the Clarkson Cup was created instead. Meanwhile, a group in Ontario, also known as the "Wednesday Nighters", filed an application with the Ontario Superior Court, claiming that the Cup trustees had overstepped their bounds in signing the 1947 agreement with the NHL, and therefore must award the trophy regardless of the lockout.
On February 7, 2006, a settlement was reached in which the trophy could be awarded to non-NHL teams should the league not operate for a season. The dispute lasted so long that, by the time it was settled, the NHL had resumed operating for the 2005–06 season, and the Stanley Cup went unclaimed for the 2004–05 season.