<P> Standardization was enforced at the Council of Trent, which suppressed regional variations in favour of the Roman liturgical rite . Most of the particulars of the resulting Tridentine Mass were already in existence in the usage of Rome . Pope Pius V permitted rites in existence for at least 200 years to continue in use; however, in the following centuries almost all rites were abandoned except those of religious orders and the afore - mentioned Ambrosian and Mozarabic liturgical rites . </P> <P> There are common elements found in most Western liturgical churches which predate the Protestant Reformation . These include: </P> <Ul> <Li> The Procession with the cross, followed by the other acolytes, the deacons and the priest </Li> <Li> The Invocation (beginning with the Sign of the Cross) </Li> <Li> Confession at the foot of the altar </Li> <Li> Absolution </Li> <Li> Introit, Psalms, Hymns, chants </Li> <Li> Litany </Li> <Li> Kyrie and Gloria </Li> <Li> Salutation </Li> <Li> Collect </Li> <Li> Liturgical Readings (call and response) </Li> <Li> Alleluia Verse and other responses </Li> </Ul> <Li> The Procession with the cross, followed by the other acolytes, the deacons and the priest </Li>

Where did the liturgy of the hours originate