Analysis
Greensleeves, and the minor key that will not settle on one scale
Eight bars of a traditional melody in E minor, in six-eight, where the sixth and seventh degrees appear now natural, now raised, and the harmony uses the major seventh-degree chord of the natural minor and the dominant of the harmonic minor within the same passage.
Greensleeves is the minor-key melody more people know than any other, and it is a lesson in what the minor key does that is strange: the same phrase uses the natural seventh degree in one bar and the raised one in the next, and the harmony follows, with the chord on the natural seventh degree and the dominant with its leading tone a few bars apart. The version below is one of the current ones; the melody has circulated in variants since the sixteenth century, and none of them is the "right" one.
Six-eight, two pulses
The metre is six-eight: two dotted-crotchet pulses, each divided into three quavers. The melody is almost all crotchet and quaver, long and short, which fills each three-quaver pulse without breaking it. Count "one two three, two two three" and the melody falls entirely on the numbers.
The seventh degree, twice
The scale is E minor, one sharp in the key signature: F sharp. At the start of the phrase the melody passes through D natural, the seventh degree of the natural minor, and the harmony under it is D major, the chord on the natural seventh degree, which does not pull towards the tonic and prepares the way to the relative major, G.
Bars later, the melody rises to D sharp, the raised seventh of the harmonic minor, and the harmony becomes B seventh, the dominant of E minor with the leading tone inside it. The same phrase, the same tonic, two minor scales: the minor field is not one field, and this melody demonstrates it in eight bars.
The sixth degree, as well
The same happens with the sixth degree. The melody uses C natural, the sixth of the natural minor, on the way down; the harmonisation with D major and G major favours that C. In one current variant the C appears sharp on the way up, and the scale in that bar is the melodic minor. Singers choose by ear; the score records one of the choices.
The cadences of the phrase
The first half of the phrase ends on the dominant, B seventh: a half cadence, the comma. The second half repeats the opening and ends on the tonic, E minor, by an authentic cadence: the full stop. Question and answer in eight bars, the shape of most traditional melodies.
What the piece teaches
That the minor key is a tonality with three scales available, and that the melody chooses between them bar by bar. That the natural seventh degree points at the relative major and the raised one at the minor tonic. And that six-eight is two pulses, not six, which you can hear in any line of this melody.
