The ‘operatisation’ of oratorio is a commonplace of the discourse around Italian music of the eighteenth century. Like all such grand generalisations, it risks drawing attention one-sidedly to the obvious and banal while overlooking less prominent features that in the end may prove more interesting and characteristic. Since its rediscovery in the late 1920s, Vivaldi’s sole surviving oratorio, Juditha triumphans (1716), has served music historians as a classic, strikingly early example of this operatising tendency. The fact that it has been readily available in more than one modern edition, as well as a facsimile edition, has often been performed and recorded and has commended itself to Vivaldians and the music-loving public alike through the high level of its musical inspiration and colourful instrumental palette only serves to accentuate its representative quality. When, in 1974, I wrote the sleeve notes for the Philips recording of the oratorio under Vittorio Negri, I had no hesitation in subscribing to this consensus. Parodying the well-known reference to Verdi’s Requiem as the composer’s ‘best opera’, I used the same epithet for Juditha triumphans. I do not regret the description, which – let it be remembered – was made at a time when very few of Vivaldi’s operas had achieved a staged, or even a concert, performance and their viability under modern conditions was doubted: in its telegraphic way it conveys something true about both the nature and the quality of the work. But a balanced view demands that we also examine the many respects in which Juditha triumphans does not adopt, or adopts only in distorted form, operatic norms. These prove to be relevant not only to the aesthetic appreciation of the work itself but also to oratorio and opera librettology in general.

What are the symptoms, some already in existence well before the end of the previous century, by which one recognises operatic influence in early Settecento oratorio? First, one notes the diminished role for the chorus, which may not exist except as an ensemble of soloists, and when it does exist separately is limited to short and simple contributions.