Calixa Lavallée
Born: 28th December 1842, Montreal, Quebec, Canada
Died: 21st January 1891, Boston, Massachusetts, United States
Nationality: French-Canadian-American
Calixa Lavallée was a French-Canadian-American musician and Union Army band musician during the American Civil War. He is best known for composing the music for "O Canada," which officially became the national anthem of Canada in 1980, after a vote in the Senate and the House of Commons. The same 1980 Act of Parliament also changed some of the English lyrics. A slight alteration to the English lyrics was made again in 2018.
Read more at https://en.wikipedia.org/wiki/Calixa_Lavallée