In 1979, the Oilers joined the National Hockey League alongside the Winnipeg Jets, Hartford Whalers and Quebec Nordiques to round out the league at 21 teams. It was a huge moment for Edmonton, especially as the city got to showcase their young star Wayne Gretzky, who went on to become the greatest player in league history. But how did the Oilers go from a start-up team in a secondary league to the highest level of play in the world in less than a decade?

The team started in 1971 with the founding of the World Hockey Association, and three owners that wanted to bring big time hockey to the city. One of the owners, “Wild Bill” Hunter already had a professional team in what’s now the Western Hockey League, the Edmonton Oil Kings. Hunter wanted an NHL team badly, but after being turned down so many times, went with the new WHA.

Trouble was brewing for the league before the first season even started as Calgary’s team, the Broncos, folded and were absorbed by the Oilers. While the team had some star players and good attendance, there wasn’t a lot of success throughout the 1970s. One acquisition was notable, though, as Glen Sather joined the franchise initially as an aging player, but remained with the Oilers in some capacity for the rest of the 20th century.

Fans continued to churn out to see the team that was considered “average” by many, and then came the biggest stroke of luck in franchise history. The Indianapolis Racers ceased operations in 1978, and their rookie player Wayne Gretzky was acquired by the Oilers because of their financial success. 12 teams had started the WHA, but only four were absorbed by the NHL, including the Oilers. The team almost lost Gretzky as a result, but once again the finances were able to save them, as they signed Gretzky to a record deal, protecting his rights, and the rest is hockey history.