To the medieval mind, music offered a sounding measure of the world and the universe, its theory devised to prove the existence of the celestial sounds of the spheres, the muses and the company of angels. The musical discoveries of Pythagoras, embroidered by Plato and studied by Oxford music students until the middle of the last century, directly influenced composers from anonymous architects of plainsong to J S Bach and beyond, and was richly reflected in the symbolism of Shakespeare and Milton.
Besides playing and promoting ancient music, Pickett has made a feature of exploring what now appear esoteric, even bizarre, influences on its creation.
His "Heavenly Harmony" weekend encouraged audiences to consider the remarkably uniform theoretical and metaphysical backgrounds to countless works, composed before Copernicus redrafted the medieval world picture, and enlightened philosophers rejected the harmony of the spheres. Although pre-concert talks and programme book essays offered pathways into a long-defunct belief system, Pickett's challenge was to devise a programme of works that might do the same.
Handel may not be the most obvious candidate to open a mini-festival devoted to music's supernatural powers, but the plot of his opera Orlando is fuelled by the interventions of Zoroastro, a magician able to read the stars and alter destiny.
The Early Opera Company's production was a disappointment - safe in its risk-free delivery of Handel's score, underpinned by bland singing and a minimalist staging that involved the cast in fussy gymnastics with seven symbolic spheres and much slithering around a crescent-shaped impediment. Zoroastro, robustly but not passionately sung by Matthew Hargreaves, appeared more like Michael Palin's Monty Python castaway than a plausible presiding genius, irritatingly amusing in floor-length dreadlocks and matted beard. Louise Mott sounded uncomfortable in the title-role, unable to make the most of her impressive mezzo tone in Orlando's low-lying music and only coming to life in coloratura passages. Conversely, Geraldine McGreevy was well cast as Angelica but rarely willing or able to alter the colour if not the dynamic of her voice.
Earlier territories were explored with greater success by the Catalan gambist Jordi Savall and his ensemble Hesperion XX, and by the New London Consort, revisiting the visionary world of Gautier de Coincy's Miracles de Nostre-Dame and presenting a flawless, intensely moving, semi-staged account of the 13th-century cleric's work.
After a rather subdued look at dance works by Ortiz, the Hesperion XX programme turned to secular songs (or tonos humanos) by the priest, robber and serial murderer Jose Marin, expressively and seductively sung by Savall's wife, Montserrat Figueras, and given irresistible spirit by the flamenco-style improvisations of guitarist Rolf Lislevand and Adela Gonzalez- Campa's articulate castanets. Here were the fruits of a group that gets to know its repertoire, lives with it for months in rehearsal and then enjoys the business of performing it.