Bergen may have been founded on the medieval demand for dried cod, but today Norway’s second city trades primarily in an altogether more rarified commodity: culture.

The annual Bergen International Festival – described by incoming artistic director Anders Beyer as ‘the crown jewel of cultural activity in Norway’ – celebrates its 60th anniversary this month, with performances by Berlin’s Komische Oper, Les Arts Florissants, Bryn Terfel and of course Leif Ove Andsnes marking the end of Per Boye Hansen’s eight-year tenure, and hints of next year’s programme anticipating a new era under Beyer.

With Bergen caught in a rare heatwave, the bucolic frolics of this year’s festival opener – Stefan Herheim’s new production of Xerxes, fresh from Berlin – make strange sense. Sheep graze under King Xerxes’s beloved plane tree, man-sized and aggressively over-sexed, setting the tone for an opera none-too-seria that filters the cross-dressing, cross-cast action as through the fantastical haze of a summer afternoon’s siesta.

The relentless insistence on meta-theatre can feel rather dated at times (not helped by conductor Konrad Junghänel’s leaden speeds in the pit) but Gesine Völlm’s playful costumes and a strong cast led by Stella Doufexis’s Xerxes redeem absurdity and transform it somehow over the course of three hours into a poised piece of dramatic kitsch. In Katarina Bradic’s resonant Amastris the Komische Oper have a star, and her performance alone makes this a production worth travelling for.

Offering fewer visual jokes but every bit as much musical colour, a visit from Bergen’s own Leif Ove Andsnes and the Mahler Chamber Orchestra marked the inauguration of the Bergen Philharmonic’s new grand piano. Directing Beethoven’s First and Third Piano Concertos from the keyboard, Andsnes showcased not only the bright tone of the Steinway but his own impossibly fluid technique. Cadenzas dripped with scalic embellishment, and the fragile intensity of the opening Largo theme from the Piano Concerto No 1 seemed indefinitely suspended in a web of pianissimo strings. Only in the Piano Concerto No 3 did Andsnes’s technique seem to work against him, offering too smooth, too polite a reading of this angst-filled work.

With concerts split between the city’s main Grieghallen, the medieval cathedral, and Grieg’s own summer house of Troldhaugen (even taking over the streets, as the Venezuelan Brass Ensemble did this year) as well as theatre, dance and film events, the Bergen Festival has many different spaces and faces to unite into its programming. Its diversity is a strength, but one Beyer is keen to continue to balance with a sense of a distinctively Nordic identity.

‘The idea of just letting a touring classical star end their tour in Bergen is not interesting for me or audiences. We have a word in Norwegian which doesn’t translate, but is to do with the community spirit – those things that connect us. The folk-culture, the choral tradition, the accordion in the countryside – all of that is important, not the international podium culture.’