thought the "40" was in error, and removed the extra zero). Davitt Moroney claims that it was only in July 2005 that he recovered and identified the work. What was subsequently publicised as its first performance in modern times was on 17 July 2007 at a Proms concert in Royal Albert Hall in London, where it was sung by the BBC Singers and Tallis Scholars, with His Majestys Sagbutts & Cornetts, conducted by Moroney. However, the website of the Spanish record company Glossa states that their recording of the work uses an edition made in 1978 by French counter-tenor Dominique Visse. It is not stated there whether Visse identified the piece as being by Striggio, or whether he performed it, at that time. In 2011 what was claimed as the "World premiere recording" of the Mass had been issued by Decca; it is performed by I Fagiolini under the direction of Robert Hollingworth. A third CD recording, by Moroney himself, has not yet been issued. Music Unlike the massive polychoral compositions of the Venetian School, in which performance groupings were positioned in lofts across from each other in a large space, the choirs in Missa sopra Ecco sì beato giorno were probably not meant to be significantly spatially separated. Although Striggio left no performance directions, the most likely arrangement was for the singers to be positioned in a large semicircle, with the instrumentalists in its center, in view of the singers. The exact instruments used, and their number, is not known, but probably varied from performance to performance. An unusual feature of the mass is the existence of two partbooks for a Bassus ad organum, a part which doubles the composite bass line of the entire composition. Presumably Striggio used this as a compositional tool, to keep track of the harmonies as he wrote forty to sixty voice parts above it; it also foreshadowed the development of the basso continuo in the 17th century. The Missa sopra Ecco sì beato giorno is probably a parody mass, i.e. one based on a pre-existing polyphonic work, in this case named "Ecco sì beato giorno". However, no song of this name has yet been found: it may be a lost work of Striggio himself, or may even be a reference to his similarly titled 40-voice motet Ecce beatam lucem. The repetition of musical phrases at certain key points in the Mass suggests use