It hardly takes a special occasion to point out the historic ties between Orkney and Norway:

just look at any street map of Kirkwall or the surnames in any Orcadian graveyard. The islands are officially twinned with Hordaland County (the region of fjords and skerries around Bergen) and every year a huge Norwegian Christmas tree arrives in Kirkwall to symbolise those ancient links across the North Sea.

One of several anniversaries being marked at this year's St Magnus Festival - Orkney's prestigious midsummer classical music series - is the 200th year of the Norwegian constitution, signed on May 17, 1814. At the time it was considered (apart from the minor concession of retaining a monarchy) the most radically liberal constitution in the democratic world; today it is the third oldest constitution still in operation, and its generally progressive ethos is reason enough to celebrate.

For Alasdair Nicolson, Scottish composer and artistic director of the St Magnus Festival, it's an excuse to declare an official Norway theme to this year's programme. Think everything from talks on ancient Norwegian archaeology to contemporary Norwegian music, visual arts, cuisine and, er, knitting. (We'll come back to that.)

The Trondheim Soloists and the terrific oboist Nicholas Daniel open the festival on midsummer's eve with a programme that includes Norwegian composer Henning Sommero's Rex Olavus alongside a work by Alasdair Nicolson called simply Magnus. There's more from the Trondheim lot throughout the festival: they play Grieg (of course) and Peter Maxwell Davies's Start Point, and in a particularly alluring programme they venture to the Orkney Brewery for a concert accompanied by specially-concocted morsels by the Norwegian forager-chef Mikael Forselius. As for the knitting: I have it on good authority that Norwegian duo Arne and Carlos are "celebrity knitters" and will be in residence for workshops at Kirkwall Community Centre.

Another Scandanavian connection comes in the figure of Hugo Ticciati - big brother of Scottish Chamber Orchestra principal conductor Robin, and by all accounts a superb violinist; he doesn't perform much in the UK, so his late-night solo recital in St Magnus Cathedral will be my first chance to hear him. Why does an English violinist with Italian heritage present a Scandinavian connection? Because Ticciati is based in Sweden, where as well as teaching and performing predominantly contemporary Scandinavian music he also runs his own festival, Stockholm's O/MODORNT.

"Hugo is my kind of person," says Nicolson. "He'll have the maddest ideas, but not just have them but do everything in his power to make them happen. He's a fascinating programmer. You would almost think he was a composer when you look at his programmes."

This last remark hints at Nicolson's own approach to programming St Magnus: he sees his role as a composer as integral. "It's like gardening, like cooking, like composing, like architecture - all things I'm passionate about," he says. "A festival programme is a bit like composing a piece of music but with much bigger blocks. I do interfere quite heavily with what's being performed. I don't just invite musicians; I'm keen to make threads across the whole thing, to keep themes in play."

He hints at what those threads might be for next year's festival: codes and numbers - Maxwell Davies's magic squares, Shostakovich's covert political intimations, the love saga encrypted into Berg's Lyric Suite.

But back to this year's programme, and more anniversaries. It has been 70 years since the release of Orkney's Italian prisoners of war, who were brought to the islands in 1942 to build the Churchill Barriers across Scapa Flow and freed two years later - but not before building a tiny Catholic chapel out of two Nissen huts on Lamb Holm.

It's an extraordinary place, constructed largely out of salvaged materials and meticulously painted by a soldier from Moena to depict frescos and stained glass, vaulted ceilings and soaring buttresses. The intimate acoustic of the Italian Chapel is perfect for sweet-voiced early music; on midsummer's night, the Italian ensemble Laus Concentus performs lute songs by Monteverdi, Lasso, Caccini and others.

Never far from the heart of the festival is Peter Maxwell Davies. The festival's co-founder and long-time director turns 80 this year. His birthday is being honoured across the UK, with dedicated Proms concerts and orchestral programmes in Glasgow in September. St Magnus has chosen a slightly different slant to its celebrations. School choirs from across Orkney will perform his Songs of Hoy (words by George Mackay Brown), the choral song cycle Seven Songs of Home and Kirkwall Shipping Songs.

Some of Maxwell Davies's more serious vocal music will also be performed by the BBC Singers - including the rarely-done Westerlings, a tremendously difficult piece from the 1970s. But for Nicolson it's the children's songs that highlight the special impact that Max has had on the islands during the four decades he has lived there.

"He has really explored the idea of the composer in the community," says Nicolson. "The idea that there can be many strings to one's bow; that you might not always want to write concert music, that you might write for schools or theatre - or indeed run a festival."

Placing new music at the core of the festival from the outset means today's St Magnus audiences are happy to take risks, says Nicolson. "Contemporary music doesn't put them off. They've also got used to meeting the composers. That sense of engagement, of knowing that composers can be ordinary people is invaluable."

As proof, he tells me: "Not only do I programme the festival and sometimes compose music for it, I write all the programme notes, collect all the artist biogs - I was in the kitchen at the London launch, making the canapés." A wealthier festival would outsource, but St Magnus runs on just three full-time staff members and spends the vast majority of its budgets on artists' travel to and from the remote islands. "Thank God we have such an tremndous army of local volunteers," says Nicolson. "Somehow it all comes together."