The Worcester Fragments are the most important surviving collection of English medieval polyphony. Dating from about 1235 to 1350, they include over a hundred sacred compositions including these two Alleluias. Alleluia Nativitas is probably one of the earliest pieces in the collection and is in the style of Parisian organum; indeed, it quotes from Perotins setting of the same text. Alleluia Moduletur dates from later in the thirteenth century and has the singers exchanging melodies in typically English rondellus fashion. For two solo singers plus a small choir for the intervening plainchant. i + 13 pages.