The Gospel reading for the 17th Sunday in Ordinary Time (Year A) is taken from Matthew (13: 44-52) ‘The kingdom of heaven is like…’ (Simile est regnum cælorum), a text repeated in the Communion Antiphon. Victoria’s Mass is a parody of Guerrero’s motet of the same title; however, the text of Guerrero’s motet is a different simile from later in Matthew’s Gospel (20: 1-4), so, while Victoria’s Mass ties in liturgically in title, if not in origin, Guerrero’s motet doesn’t. Instead, we are singing his wonderful motet Ave Virgo sanctissima which, far from being a random choice, fits in in two ways.