Sebald Heyden, German musicologist and theologian (d. 1561)
Sebald Heyden (8 December 1499 – 9 July 1561) was a German musicologist, cantor, theologian, hymn-writer and religious poet. He is perhaps best known for his De arte canendi ("On the Art of Singing", third installment published 1540) which is considered to have had a major impact on scholarship and the teaching of singing to young boys. He wrote hymns such as "O Mensch, bewein dein Sünde groß". It has been speculated that Heyden was the world's first true musicologist.