I always think that a music festival should present something different – better, more unusual, more challenging – than the average run of musical life. Well, Dresden yesterday pulled a rarity out of the hat, an opera by Princess Amalie of Saxony (1794-1870), a member of the Wettin dynasty and a one-time pupil of Carl Maria von Weber. The score of her comic opera La casa disabitata was looted by the Russian at the end of the Second World War and has only just be retrieved in time for a revival some 180 years after its premiere. 

The work – one of 17 operas that Amalie wrote – is couched in a musical language that fits into the Mozart-Cimarosa-early Rossini vein. It's charming and occasionally surprisingly engaging with its vivid colours and original orchestral effects; Amalie makes great use of the woodwinds and has an appealing musical voice.

The cast of mainly young singers based in Dresden (quite a few are attached to the opera here) was a good one with some very fine individual performances: I was much taken with the American bass-baritone Allen Boxer (as Callisto) and the German soprano Anja Zügner (as Annetta). The Korean bass Ilhun Jung as the landlord of the 'uninhabited house' of the title was a strong presence and received by far the best number of the work, complete with pizzicato accompaniment. The central role of the poet Eutichio was attacked with a typically buffo broad brush by Matthias Henneberg, notably older than his colleagues. Helmut Branny directed the Dresdner Kapellsolisten and the whole thing was given (in concert form) in the delightful Palais im Grossen Garten, a small palace whose imposing exterior contains a charmingly delapidated salon that's perfect for small-scale performance. It was a lovely way to spend an hour and a half on a Sunday afternoon.

The evening concert at the Semper Opera House - which doubles as a concert-hall for the Staatskapelle Dresden – found Valery Gergiev and the Mariinsky Orchestra in town. I must admit to being a bit of an agnostic when it comes to Gergiev's industrial style of music-making, a tireless roadshow that veers between the heart-stoppingly inspired and the decidedly hum-drum. In a programme of Bartók, Honegger, Richard Strauss and Liadov we glimpsed the whole gamut of Gergiev's music-making. 

Bartók's Miraculous Mandarin whipped up a lot of noise but lacked menace, and the episodic nature of the score (it is a ballet after all) was all-too-apparent. Gergiev's nose was constantly in the score, as it was - perhaps not surprisingly – for the Honegger Cello Concerto with the Festival's intendant Jan Vogler as soloist. It's a strange piece with some utterly ravishing moments and some oddly grey ones too, but the performance was a fine one, and Vogler certainly convinced me that it's worth the occasional airing. A little solo Bach brought the house down as the Dresden audience rooted for their boy.

To play Strauss's Ein Heldenleben in a Strauss city like Dresden is either madness or excellent manners. Gergiev's reading was fine, but I have to admit that my Heldenleben 'bar' is set very high as my first experience of the work, live, was conducted by Karajan – and that was a performance that remains etched on my memory. The surge of the work, its sudden changes of mood and surprising colours were all nicely done, but rarely was there the space around the notes that the great Straussians instinctly give us (just think of Rudolf Kempe, recorded in this very city), and the solo playing of the Mariinsky Orchestra's leader, Kirill Terentyev – beautifully played per se – lacked that languour and elegance that a Michel Schwalbé or a Thomas Brandis offered chez Karajan. But then, as an encore, Gergiev gave us – without the score this time – Liadov's The Enchanted Lake – a performance approaching perfection. I guess this is the equivalent of an English orchestra doing something like Delius's A Walk to the Paradise Garden; the idiom totally embraced, the colours exquisite, the mood sustained perfectly. I'd have happily sat through it two or three times over so lovely was it as orchestral playing – and the Mariinsky ensemble in full sail is up there with the best.