YORK Early Music Christmas Festival welcomes back Stile Antico ten years after they won the Friends of York Early Music Festival prize at the 2005 International Young Artists Competition.

"Back then, they weren't sure what their future held but we in the audience all knew they had something special to offer," says singer and Classic FM presenter Catherine Bott. "And they've gone from strength to strength ever since."

"I think winning that prize was a real turning point for us," says member Kate Ashby.

"We began in 2001 as a group of student friends in Oxford, though most of us were studying at Cambridge, and singing together was just something we loved doing. I'm sure we would have still met up to perform twice a year but the York competition launched us from being friends doing something we enjoyed to having a professional status, and next year we celebrate our tenth anniversary."

On Sunday evening, Stile Antico will close the 2014 Christmas festival, when they present A Wondrous Mystery, a mixture of the formal and the informal, of sophisticated polyphony and folk-like dances. Alongside a Christmas mass by the Flemish composer Clemens non Papa will be traditional old-German carols and motets, many of them still familiar today.

Among the highlights will be Eccard's infectiously joyful Übers Gebirg Maria Geht and Praetorius's double-choir Magnificat, which incorporates the carols In Dulci Jubilo and Josef Lieber, Josef Mein.

"It's a Christmas festival, and the closer we move to Christmas, the better it feels," says Kate. "A lot of the tunes you will recognise; there's something about German Christmas tunes, and they have great Christmas cake and Christmas wine too."

Stile Antico have made one Christmas album already, 2010's Puer Natus Est (A Boy Is Born), and Wondrous Mystery will form the next one. "The programme we're doing in York will be recorded and we'll have the record out next Christmas," says Kate.

Plenty of festive engagements are coming the way of Stile Antico, with concerts in Germany either side of the York performance and today the small matter of a Royal appointment to keep. "We're performing in the Queen's Gallery at Buckingham Palace to tie in with two Buckingham Palace exhibitions, one about gold, and the other, a photographic exhibition of the then Prince of Wales travelling to the Holy Land 150 years ago," says Kate. "We haven't been told yet if The Queen will be attending."

Stile Antico first sang at Buckingham Palace last year, performing a programme of Dutch music for the Hapsburg court. "It's exciting to be singing in such surroundings again," says Kate.

Looking back over ten years of Stile Antico, she picks out such highlights as the 2007 release of their first album, Harmonia Mundi, Music For Compline.

"It was nominated for a Grammy award and was picked up by the National Public Radio stations in America, and since then we've toured the United States once or sometimes twice a year," she says.

Stile Antico continue to be Kate's primary musical activity, although she has done some teaching and other singing engagements too. Meanwhile, Stile Antico have lost five original members through the years. "Fortunately, we have replaced therm all, so we remain a 12-piece," she says.

Stile Antico present A Wondrous Mystery, Sir Jack Lyons Concert Hall, University of York, Sunday, 6.30pm. Box office: 01904 658338 or at ncem.co.uk