The Castile monastery of Santo Domingo de Silos was built between 9th - 11th centuries. Its choir of monks is noted for the Lauds to the Virgin Mary, solemn forms of musical worship for 400 years. The ancient breviary of the monastery provides the Roman liturgy upon which the Gregorian chants are built. The chants - recorded 40 years ago - celebrate God’s relationship to Mary and invite the audience to praise Her grace. The music has been arranged to proceed with a sense of variety of styles: pneumatic and melismatic (a single syllable moving between several notes in succession) liturgy is mixed with antiphonies (responsive singing by two choirs), canticles (non-metered words from the Bible), sequences, prose, chants, hymns, introits (psalms sung as the priest approaches the altar for the Eucharist), graduals, and alleluias (joyous praise in song). The male choir, unless a cappella, has only the organ to provide a bass tone and underlying pedal point.