"O Canada" is the national anthem of Canada. 

The song was originally commissioned by Lieutenant Governor of Quebec, Théodore Robitaille, for the 1880 Saint-Jean-Baptiste Day ceremony.   Calixa Lavallée composed the music, after which words were written by the poet and judge, Sir Adolphe-Basile Routhier. The original lyrics were in French; an English translation was published in 1906. Multiple English versions followed; however,  Robert Stanley Weir's version in 1908 gained the most popularity, eventually serving as the official lyrics enacted by Parliament. 

Weir's lyrics have been revised three times, most recently when An Act to amend the National Anthem Act was enacted in 2018.  The lyrics changed from "all thy sons command" into "all of us command" to reflect a more inclusive reality of Canada.  The French lyrics remain unaltered. "O Canada" had served as a de facto national anthem since 1939, officially becoming the country's national anthem in 1980 when Canada's National Anthem Act received royal assent and became effective on July 1 as part of that year's Dominion Day celebrations.  

Watch new Canadians sing O Canada at a hockey game. 

https://youtu.be/TTN0NDL2bA0