The Gregorian song is named as a tribute to pope Gregor the great who lived in the 5th century A.D. The terms were not described until around year 1000. The names referes to the modes used by the Greek. However the monks did not intepret the Greek writers right. The Greeks always described their scale from the top tone, while the monks started from the bottom tonic.
|Scale tones on a piano||Name today||Ancient Greek names|