The American Hockey League is a minor professional ice hockey league in the United States and Canada. It serves as the top developmental league for the National Hockey League. The league played its first season in 1936 as the International-American Hockey League, a "circuit of mutual convenience" formed when the Northeast-based Canadian-American Hockey League and the Midwest-based International Hockey League agreed to play an interlocking schedule. After two seasons, the leagues formally merged into a unified league under the IAHL name. After the 1939–40 season, the league became known as the American Hockey League.