“Let there be no-one who, in despair, gives himself up to grief, though at times it may powerfully assail us and darken our lives.” The Shepherds’ message, delivered with deliberate irony early in Orfeo yet summarising its final moral, might also have been Monteverdi’s private mantra as he suffered indignity after indignity at the hands of Vincenzo Gonzaga, Duke of Mantua. For over 20 years the Gonzagas paid him late, ignored his personal tragedies, and treated him in all practical terms with cruel contempt. Monteverdi, nevertheless, created extraordinary music in the Gonzaga court (before moving, at last, to Venice in 1613, where he would soon be properly appreciated): and top of the list of his Mantuan achievements must come the groundbreaking Orfeo, his favola in musica (musical fable), often called the first ‘true’ opera. Hope may abandon Orpheus at the gates of hell, but Monteverdi’s constant sense of invention shows that the many frustrations of his Mantuan life could never entirely dominate his creative spirit. Sir John Eliot Gardiner presided over a superb Orfeo for the Proms which made the most of Orfeo’s experimental aspects – and deliriously beautiful score.

With sharp drumbeats and a trembling tambourine, the Monteverdi Choir made their way onto the Royal Albert Hall stage in dramatic procession to form a crescent on steps behind the orchestra, the shepherds in black shirts and trousers, the nymphs in simple but jewel-bright block-colour dresses. John Eliot Gardiner had divided the English Baroque Soloists into two halves, creating a stage-like gap at the centre of the instruments in which nymphs could come forward to dance and principals could sing in fully-acted character. As the evening unfolded, the action spilled out into the Prom pit and even the amphitheatre, keeping the audience on their toes: you never quite knew from where the next solo might suddenly spring. Monteverdi’s experiment was alive.

Gardiner’s English Baroque Soloists looked a forlorn, tiny band in comparison to the musical army amassed by Donald Runnicles for Verdi’s Requiem, but they created an expansive, vivid Baroque sound which soared easily around the hall. The sumptuous timbre of their Baroque instruments, and John Eliot Gardiner’s brilliant touch for Monteverdi, gave the music an indulgently authentic feel. The Monteverdi Choir were in fabulous voice, singing with festive joy in pastoral scenes, polished serenity in their supernatural incarnations. As shepherds and nymphs, their clapping and dancing for “Lasciate i monti, lasciate i fonti” had such gusto it almost drowned all other playing: a brave decision which added a certain crazy life to the stage, but unforgiven by the Royal Albert Hall’s petulant acoustic.

Krystian Adam’s luxuriously velvety tenor, with airy top and luscious low notes, gave us a heartbreaking Orpheus. With his magnetic stage presence, Adam’s superb acting and charismatic delivery would have constantly drawn the eye whatever happened: and his singing was consistently spellbinding. Adams was able to achieve astonishing effects, particularly when sustaining a long, controlled pianissimo (in which a dropped pin would have clattered), or conveying mood clearly by subtly colouring his voice, here jubilant, there impassioned, next abjectly despairing. Adam’s focused, emotionally charged Orpheus was every inch the rock star demigod.

Francesca Aspromonte got us off to a glorious start as Music, her voice soon settling into an expressive soprano of lyrical beauty, stalking the stage like a real goddess and singing with joyous flair. Aspromonte also endowed her Messenger nymph with languorous pathos, winding her way slowly and mournfully right through standing Promgoers as she reluctantly approached Orpheus to give him the bad news which sends him down to Hades in search of his beloved.

Despite her lithe and elegant dancing, uneven projection and simplistic overacting from Mariana Flores didn’t achieve much beyond simple prettiness with either Eurydice or Hope until Eurydice’s final “Ahi, vista troppo dolce”, which was beautiful. Andrew Tortise’s Apollo had regal poise: “Dunque se goder brami immortal vita” brought with it a new sense of rapture, making the most of Monterverdi’s dramatic shift of atmosphere here. Gianluca Buratto was a nicely grumpy Charon and vibrantly sensual Pluto, and Francesca Boncompagni an accurate but unexciting Proserpina. James Hall’s sweet countertenor exhibited some nicely cool turns for the Third Shepherd. Gareth Treseder (Second Shepherd, Spirit 2) kept doing something so peculiarly harsh with his “a” vowels that it distracted me completely, though it was fun to hear his Echo emanating from some invisible position in the Gods.

As four nymphs danced merrily around John Eliot Gardiner for the closing Moresca, the sense of inventiveness persisted: how strange, yet fitting, that this oldest of operas should still feel so fresh.