The Stanley Cup is a trophy awarded annually to the playoff champion club of the National Hockey League (NHL) ice hockey league. It was donated by the Governor General of Canada Lord Stanley of Preston in 1892, and is the oldest professional sports trophy in North America. Inscribed the Dominion Hockey Challenge Cup, the trophy was first awarded to Canada's amateur ice hockey clubs who won the trophy as the result of challenge games and league play. Professional clubs came to dominate the competition in the early years of the twentieth century, and in 1913 the two major professional ice hockey organizations, the National Hockey Association (NHA) (forerunner of the NHL) and the Pacific Coast Hockey Association (PCHA), reached a gentlemen's agreement in which their respective champions would face each other in an annual series for the Stanley Cup. After a series of league mergers and folds, it became the de facto championship trophy of the NHL in 1926, though it was nominally still subject to external challenge. After 1947, the Cup became the de jure NHL championship prize.