This piece is really strange! It is originally an orchestral prelude (an "Air") to an opera scene, where the hero is sleeping. Perhaps he has nightmares? This anonymous theorbo arrangement of Lully's piece "Les Sourdines d'Armide" (tragedie "Armide", 1686) is from manuscript Vm7-6265 Bibl. Nationale, Paris, possibly written at the very end of the 17th century. The arranger _could_be_ de Visee, because the ms. has lots of music by him. The instrument is "Théorbe de pieces" in d (a'=392). Actually I have stringed and tuned my archlute (Stephen Barber, 1987) to a high theorbo. More French theorbo music in page cs.helsinki.fi/u/wikla/mus/Tiorba/deVisee/. Arto Wikla 9.5.2009.