An epic piece of music composed by Englishman Thomas Tallis will be performed later this week at Truro Cathedral by eight choirs.
It is thought Tallis's masterpiece was in response to a challenge laid down by the Duke of Norfolk, during the reign of Queen Elizabeth I.
The Duke had seen a copy of a 30 – or possibly 40 – part motet by an Italian composer and asked if there was any Englishman with the skill to write in this many parts.
Tallis's response was Spem in alium.
Truro Cathedral's director of music, Christopher Gray, is preparing to conduct the piece for the second time.
He said Tallis was one of Britain's greatest composers and Spem in alium dates from about 1570.
Mr Gray said: "The conception is staggering – 40 independent parts, each sung by at least one singer.
"There are eight choirs, each with soprano, alto, tenor and two bass parts.
"The mental challenge of composing a piece like this is breathtaking.
"I hope to lay the eight choirs out in a large semicircle to make full use of the various special effects in our wonderful cathedral acoustic."
The concert takes place this Sunday at 7.30pm.
The rest of the hour-long concert includes a variety of music sung by the Gentlemen of Truro Cathedral Choir.
A major recent work by Russell Pascoe will feature, with barbershop arrangements of pop classics sung by the Cathedral Choral Scholars.
Tickets cost £7 and are available on the door. Under-18s may attend for free.
Proceeds will go towards the Cathedral Choir Tour Fund.