Canberra International Music Festival director Roland Peelman on theatre in music

Opera, particularly once the burghers of Venice made it their own preferred form of entertainment, forced music to adopt a more overtly theatrical style. Either by wallowing in virtuosic showmanship (the cult of the long-limbed castrati), or by reinventing the twists and turns of hard won "rhetorica", a dynamic and direct relationship between performer and audience was forged. You might well say that theatre and music had always been willing bed partners and that the rolling hexameters of the oldest epics in Western civilisation were once sung by a mythical bard called Homer. Indeed, music does not exist without performance. It needs charismatic, divinely gifted musicians to take up Orpheus' lyre again and again.

Three thousand years after Homer, driven by the digital revolution and a 24/7 media cult, society has become another incarnation of Shakespeare's dictum "All the world's a stage". We now find ourselves in a continuous theatre of Everyman's trivially contrived reality. Late-night yawns are as much part of the performance as early morning bathroom routines. A dog doing a dance routine on hind legs can create a Facebook following overnight. So, in this day and age, how do you explain the difference between a violinist with colourful stage histrionics and a circus clown with uncanny ability on the trombone? Paganini's devilish podium demeanour and Liszt's fay but grand gesticulations in the 19th-century concert halls paved the way for musical spectacle that wouldn't just please the ear but also excite all the other senses. The magnetism exuding from the great romantic virtuosi must have been every bit as overwhelming as the teenage hysteria that welcomed the Beatles in Australia.

Great artists make you watch and listen. When we are in the presence of that indefinable quality that hints at alchemy, even forbidden substances, we might close our eyes and blissfully drift away. But closing our ears would be more difficult. Imagine yourself in the early days of opera, long before electric power made everything visible, listening to the trotting of the horses and the clattering of the weapons in Monteverdi's Combattimento, clever sophisticated string innovations they were. But it would mean nothing if it wasn't for the dramatic framework. The story is simple enough, a celebrated episode from Tasso's crusader epic: Tancredi, a Christian knight, falls in love with Clorinda, an Arab princess. Being in opposing camps and concealed in full armour, they engage in combat during which Tancredi fatally wounds Clorinda.

The composer sets up a double device: a narrator who in as lively a fashion as possible paints the action in words and music, versus the action of the protagonists themselves. Either level can be perceived as foreground or background, the narration as voice-over in modern cinema terms or as "singing head" a la Alan Bennett. The tragic fight between Tancredi and Clorinda can be seen and heard as realistic action or as a dramatic shadow of the narration we are told. It is as if Monteverdi sensed the eternal ambiguity between music, which needs a live performer to exist at all, and theatre, which by definition requires the presence of an audience as a sounding board. We can close our eyes and hear the play unfold or we can observe and emphasise with the narrator's skill and compassion. He becomes our interlocutor, the person who looks us in the eye and invites us inside the tableau to become active participants in a pity tale.

Roland Peelman is artistic director of the Canberra International Music Festival. The festival runs from April 28 to May 8.