The diagram above shows the relationship of the planets to the four elements of the sublunary world and to the four humours or bodily fluids; it also shows how the musical modes are related to the fundamental notes generated by the movement of the planetary spheres and what effects they might have. There were many variations of these ideas, but all agreed that the planets influenced the minds of men, and that music could enhance and control these influences. As medical studies based on observation and dissection advanced through the century, the link between the old model and medicine grew weaker, though you still find allusions to the humours in literature well into the 18th century.
In the sixteenth century, Florentine hermetic philosophers such as Marsilio Ficino studied these effects of music. Ficino himself wrote magical hymns to call down the angels of the spheres, the gods of the planets – a fascinating recording was made a few years ago experimenting with the reconstruction of Ficino’s hymns (‘Secrets of the Heavens’ produced by Riverrun Records ).