History
The Stanley Cup was originally a challenge trophy, meaning that it was pretty much like a boxing championship: The champion held onto it until defeated by a challenger.
Theoretically, any amateur Canadian team could challenge for the trophy, but it was up to the cup trustees to sort out the pretenders from the contenders and decide which challengers were worthy.
At first, there was a single challenge match, but in 1901 the trustees changed to a best-of-three series, and in 1903 it became a two-game, total-point series.
The amateur era ended with the 1910-11 season, when the cup was awarded to the champion of the newly-organized, professional National Hockey Association, although other teams were still free to challenge the NHA champ.
Another professional league, the Pacific Coast Hockey Association, began play in 1912-13. That marked the beginning of annual post-season series between the Eastern and Western champions.
When the Portland, Oregon, team joined the PCHA in 1914, the cup trustees ruled that the Stanley Cup was symbolic of world hockey supremacy, allowing teams from the United States to challenge. In 1917, the Seattle Metropolitans of the PCHA became the first U. S. team to win the cup.
The NHA was succeeded by the National Hockey League before the 1917-18 season and a third league, the Western Canada Hockey League, entered the mix in 1921-22.
For the next three seasons, the Stanley Cup playoff had a triangular format, with all three league champions involved, and the NHL staged its own two-team post-season series to determine a champion.
The PCHA folded after the 1924-25 season and the WCHL was reorganized as the Western Hockey League the following year. But the WHL also went out of business after just one season. Since then, the NHL has had sole control of the Stanley Cup.
