NINE amateur singers will on Tuesday perform what is believed to be the world premiere of a major choral work - more than 400 years after it was written.

William Byrd, one of England’s great early composers, first penned his famous Mass for Four Voices in about 1592.

Fifteen years later he added a set of short motets, known as gradualia, designed to be interspersed with parts of the mass when it is used in a church worship setting.

Fragments have since become popular performance pieces with modern choirs but Father Andrew Horsman, of All Saints North Street in York, believes that the complete set has probably never been performed as Byrd intended, "It's quite possible that these songs were never used together for public worship, even in Byrd’s lifetime," he said.

"A lot of Byrd’s music was intended for private use by groups of outlawed Catholics who would have met and worshipped in secret.

"There are no records of the whole work ever being sung openly for the benefit of a church congregation.

"So, astonishing as it sounds, we may actually be giving a world premiere here, even though the music was written 400 years ago and parts of it have been popular ever since."

Fr Horsman's new group of singers, calling themselves the Clerkes of All Saints North Street, will give the first public rendition in the York church as part of a historically accurate service of Candlemas.