Gregorian chant
Usually men and boys sang Gregorian chant in churches, and holy women and men sang Gregorian chants in their daily prayers. In Roman Catholic churches, prayers and songs follow an order called the "Roman Rite."  Gregorian chant is the music used in the Mass and the Office of the Roman Rite. The "Mass" is the part of the Roman Rite where Catholics receive what they believe to be the body and blood of Christ. The "Office" is the part of the Roman Rite where holy men and women pray at special times every day.  In the past, people sang different songs in parts of Europe, but Gregorian chant replaced almost all of them.  Although the Roman Catholic Church no longer requires people to sing Gregorian chants, it still says that Gregorian chant is the best music for prayer.