The maple leaf has been used as a Canadian emblem since the 18th century. It was first used as a national symbol in 1868 when it appeared on the coat of arms of both Ontario and Quebec.
By proclaiming the Royal Arms of Canada, King George V in 1921 made red and white the official colors of Canada; the former came from Saint George’s Cross and the latter from the French royal emblem since King Charles VII. These colors became “entrenched” as the national colors of Canada upon the proclamation of the Royal Standard of Canada (the Canadian monarch’s personal flag) in 1962.
The number of points on the leaf has no special significance; the number and arrangement of the points were chosen after wind tunnel tests showed the current design to be the least blurry of the various designs when tested under high wind conditions.
Extensive historical information and a review of the many flags that have flown over Canada through the years is available elsewhere.