Montezuma, King's Theatre, Edinburgh

Continuing its theme of the clash of cultures between the Old and New Worlds, the Edinburgh International Festival has co-produced a rarity, Montezuma, by the 18th-century German Carl Heinrich Graun, with a libretto by his employer, King Frederick II of Prussia.

The destruction of the Aztecs and their civilisation by the Spanish Conquistadors reflected colonialism at its most vicious. Claudio Valdes Kuri's production, lacking focus and freshness of ideas, represented opera direction at its most feeble.

The Argentinian conductor Gabriel Garrido drew stylish playing from the period-instrument Concerto Elyma while the singing – particularly from the Italian counter-tenor Flavio Oliver flexing his muscles as Montezuma, and the valiant Mexican soprano Lourdes Ambriz as his put-upon fiancé Eupaforice – was decent enough.

After two acts with traditional though poorly designed costumes and a set based on Aztec pyramids, the opera ended in contemporary carnivalesque craziness with music by Luis Antonio Rojas, based on a work by a Mexican contemporary of Graun, Manuel de Sumaya. It may be part of Aztec culture to rip the heart from a living body, as the deified emperor did here, but that is no excuse for ripping the heart from an opera which, with its serious narrative content and not unappealing mix of arias, choruses and dances, has the potential to engage instead of enrage with its mindless silliness and sleaze. A mere parody of opera, Montezuma was more Monty Python.