A growing estrangement between the Catholic church in the West and the Orthodox church of the East in thefirst millennium led to a break between them in the 11th century, and the two regions diverged in matters of theology, liturgy, and disciplinary practices. Within WesternChristianity beginning with the 16th - century Reformation, the Roman Catholic church came to be identified by its differences with the Protestant churches.
The public worship of theRoman Catholic church is its liturgy, principally the Eucharist, which is also called the Mass. After the recitation of prayers and readings from the Bible, the presiding priestinvites the faithful to receive communion, understood as sharing in the sacramental presence of Christ. At the Sunday liturgy the priest preaches a sermon or homily, applying theday's biblical texts to the present lives of believers. The church observes a liturgical calendar similar to that of other Christians, following a cycle of Advent, Christmas,Epiphany, Lent, Easter, and Pentecost. It also follows a distinctive cycle of commemoration of the saints. The worship of the church is expressed as well in rites of baptism,confirmation, weddings, ordinations, penitential rites, burial rites or funerals, and the singing of the Divine Office. A distinguishing mark of Catholic worship is prayer for the dead.