Semi-double Green vestments

This 18th Sunday was originally (not necessarily nowadays) the Sunday following Ember Saturday with its ordinations. As these lasted until the Sunday morning, this day had no proper Mass. Later on they borrowed for this Sunday the Mass composed in the sixth century for the Dedication of the Church of St. Michael, at Rome, which occurs about this time (September 29). That is why all the chants relate to the consecration of a church (Verse of Introit, Gradual, Offertory, Communion). The Epistle and Gospel also allude to the newly ordained priests “blessed in Christ” and endowed with the power to pardon sinners.