Cistre music
The basic tuning of the cistre is E-A-d-e-a-c#'-e' (the illustration below is from Pollet's Methode).
And so, not surprisingly, many of the pieces set for the instrument are in A major. The top four strings (usually doubled) play the melody,
accompanied by the single basses which form the tonic, dominant and subdominant.
Music for the cistre is almost always in a simple two-part texture: a melodic line supported by a bass. This is uncommon (but not unknown) in the English guitar repertoire. Composers/arrangers for the English guitar treat that instrument more like a melodic instrument, sometimes with passages of thirds thirds and the occasional use of the full C major chord. Here is a typical tune of the time first set for English guitar, and below it, a cistre setting.
Much of the repertoire is indeed in A major, but D major was widely used too. For accompanying songs, the player could use a capo tasto device to change the pitch of the song and some cistres have holes in the neck between the frets to fasten a capo.
Keys other than A and D major were sometimes used. Minor keys were used occasionally too, and appear more frequently than in the English guittar repertoire.
C.F.A. Pollet and Joseph Carpentier were the most prolific producers of cistre publications. Carpentier's pieces are perhaps more sophisticated and explore a wider range of keys than Pollet's. However Pollet published at least twice as much as Carpentier, so he must have been the more popular.
The repertoire consists of songs, opera tunes, dances, duos for cistre (usually with violin) and Carpentier published some songs combining cistre, voice and violin (or flute) and mandolin.