 Similarly, in music in a minor key, composers and songwriters often "borrow" chords from the tonic major.For example, pieces in C minor often use F major and G major (IV and V chords), which are "borrowed" from the key of C major.More advanced types of altered chords were used by Romantic music era composers in the 19th century, such as Chopin, and by jazz composers and improvisers in the 20th and 21st century.