Alain Lefebure

Italian and French system call the sixth scale degree differently from German and English speaking countries.
What seems a small point is actually a profound difference in harmony and teaching conception.
The Franco- Italian system consists of two mains degrees the Tonic (I) and the Dominant (V) both surrounded by their neighboring tones. The scale is centered on the Mediant (III) that divides the fifth interval I-V


The degree VII is either the Sous tonique (Subtonic) when placed a tone under the tonic or the Sensible (Leading tone) if the interval is a semitone.Sensible is used in sense of "attracted " by the tonic)
Degree II is the Sus-tonique (Supertonique ) because above the tonic.
Degree III is the Mediante because placed in the middle of scale
Degree IV is the Sous Dominante (Sub dominant) under the dominante
Degree VI is the Sus dominante (super dominant)over the dominante

This system reminds the old church modes based on Two degrees :

1. The finale,kind of tonic , ends the piece but  has not the compelling action of  a tonic
2. The teneur , the ancestor of the dominant,is the most conspicuous degree of the mode

This system displays an ascending  conjunct line and promotes melody through voice leading using rules of counterpoint rather than chord progression. The understatement is "melody creates harmony" that opposed Rousseau and Tartini to Rameau .

The German system,centered on the scale degree I, is compound of three main degrees

1. the tonic I enclosed by its neigboring tones (VII-II)
2. the Sub dominant IV ,a fifth below the tonic
3. The Dominant V,a fifth above the tonic



This system stems from Rameau's theory on fundamental bass that was mostly spread out in Germany and lead to the stufen (degrees) theory from which Riemann evolved the functionnal harmony.

Teaching insists on Chord progression.

Here, the degree IV is Sub dominant means an inferior dominant (a fifth below the tonic)   creating the harmonic skeleton: a descending fifths series.

VI is Sub mediant because  it divides the inferior fifth

III being in the middle  of the upper fifth  is the mediant (understood superior)

The harmony creates the melody contrary to the Franco-Italian school

Actually there is not an antinomy between the two systems which share most of the voice leading rules.

It 's interesting to notice  the historical elements that perdure or disappear according to countries. Germany have retained ancient Greek notation for the  name of the notes (ABCDDE ) while  France choose the more recent medieval system (Ut re mi fa sol la si) opposite to  the name of degrees