The rediscovery of the gigantic "Mass Ecco si beato giorno" in forty parts by Alessandro Striggio (1536-1592), lost since 1726, sheds important light on the connections between music and politics in the sixteenth century. Dating from 1566-7, it is one of the most extravagant pieces ever composed in the history of music.
Here's a link to the lecture recounting the discovery by Professor Davitt Moroney, University of California, Berkeley.
To listen to the recent performance of the Striggio piece until July 24th, here's a link to the BBC Proms where it was performed as Prom 6 (alongside Tallis' Spem in Alium for which it is thought to have been the impetus) with the Tallis Scholars and the BBC Singers conducted by Peter Phillips.
Striggio's 40 part mass (60 parts for the Agnus Dei) was performed throughout Europe and in 1567 he went to England on an unscheduled stop to meet virtuosos in the profession of music. Thomas Tallis was undoubtedly one of them. Tallis' piece "Spem in Alium" may well have been composed as the result of a challenge for an Englishman to do as well.
The Guardian thought this performance was the choral event of the year, if not the decade.