Original: The NHL's first championship trophy was the O'Brien Cup, which was created by the National Hockey Association in 1910 and transferred to the NHL in 1918, after which it was awarded to the playoff champion until 1923.
Simplified: The NHL's first championship trophy was the O'Brien Trophy, which was created by the National Hockey Association in 1910 and was acquired by the NHL in 1918, after which it was awarded to the playoff champion until 1923.