Striggio Mass Found - Five 8-part double choirs

From The Recovering Choir Director who led me to Zee News:

A music scholar has rediscovered a 16th century choral work of Italian composer Alessandro Striggio in the Bibliotheque Nationale, the national library of France.

The man who found this music piece is Davitt Moroney, a music professor from Berkley.

Known as the Missa sopra Ecco si beato giornoi, this gigantic choral setting of music for the Catholic mass was composed in Florence for the Medici family, whom Striggio served as a highly paid court musician. It was sent as a gift to the Holy Roman Emperor in 1567 as one element in a campaign by the Medici to obtain a much-sought-after archducal title.

"It's one of the first great pieces to use architecture and space, with musical phrases physically moving around the ring from choir to choir," said Moroney.

The 30-minute mass, composed for a massive ensemble of five eight-part double choirs, is one of the most extraordinary artworks of the Italian Renaissance. But while references to it exist in period correspondence, the score itself had been lost since 1726.

More on the work here.