big, bigger, biggest: Renaissance composers made a sport of writing polyphony for as many voices as possible; Spem in alium is the greatest of those works in every respect
Tallis may have felt that Alessandro Striggio’s Missa Ecce beatam lucem, which was sung in London in June, 1557, had set him a challenge
the work inspired many later artists, Janet Cardiff for instance, whose installation Forty Part Motet was exhibited by the Concertgebouw in Bruges’s St John’s Hospital in 2012
the motet is a plea for divine grace; this had particular significance for the Catholic Tallis who was living in Protestant England