Scores from the past 150 years
"Library and Archives Canada brings together intriguing and historically important sheet music from the past 150 years. (Credit goes to Helmut Kallmann, a young CBC music librarian who began to collect sheet music in the early 1950s.) This website currently features sheet music published before 1900, from 1900 to 1913 and from 1914 to 1920, selected from the historical collection of Library and Archives Canada."
(PDFs and some MP3s available.)