Canada’s maple leaf celebrates its 50th birthday this week.

Once a controversial new design, replacing a red redo of Great Britain’s Union Jack, it’s now the country’s defining image.

Before it was officially selected in 1965, our now-accepted red design was the product of 40 years of decisions, drafts, and submissions from high-ranking politicians. Prime Ministers John Diefenbaker and Lester B. Pearson went back-and-forth, with the former opposed to changing the flag while Pearson lobbied for a three-maple leaf design with blue sides instead of red.

“We got thousands and thousands and thousands of letters on the campaign to save the Red Ensign,” said Sen. Marjory LeBreton, who worked in Diefenbaker’s office at the time. “They were writing to Mr. Diefenbaker because they had a champion in Diefenbaker, although we certainly were getting a lot of people writing, saying, ‘Canada was an independent country and should have its distinctive Canadian flag.'”

George Stanley designed the flag we’ve now had for half a century, which was eventually unveiled and adopted on February 15, 1965.

Video/Timeline: The Canadian Press