ProtestantismProtestantism is a branch of Christianity that follows the theological tenets of the Protestant Reformation, a movement that began in the 16th century with the goal of reforming the Catholic Church from perceived errors, abuses, and discrepancies. Protestantism emphasizes the Christian believer's justification by God in faith alone (sola fide) rather than by a combination of faith with good works as in Catholicism; the teaching that salvation comes by divine grace or "unmerited favor" only (sola gratia); the priesthood of all believers in the Church; and the sola scriptura ("scripture alone") that posits the Bible as the sole infallible source of authority for Christian faith and practice.
Mystici Corporis ChristiMystici Corporis Christi (The Mystical Body of Christ) is an encyclical issued by Pope Pius XII on 29 June 1943 during World War II. Its main topic is the Catholic Church as the Mystical Body of Christ. The encyclical is remembered for its statement that the Mystical Body of Christ is the Catholic Church. According to Mystici corporis, to be truly a member of the mystical body, one must be a member of the Catholic Church. Non-Catholics who erred in good faith could be unsuspectingly united to the mystical body by an unconscious desire and longing.
One true churchThe expression "one true church" refers to an ecclesiological position asserting that Jesus gave his authority in the Great Commission solely to a particular visible Christian institutional church—what is commonly called a denomination. This view is maintained by the Catholic Church, the Eastern Orthodox Church, the Oriental Orthodox communion, the Assyrian Church of the East, the Ancient Church of the East, the Christian Churches/Churches of Christ, the Churches of Christ, and the Lutheran Churches, as well as certain Baptists.
Christian theologyChristian theology is the theology of Christian belief and practice. Such study concentrates primarily upon the texts of the Old Testament and of the New Testament, as well as on Christian tradition. Christian theologians use biblical exegesis, rational analysis and argument.
DonatismDonatism was a Christian sect leading to a schism in the Church, in the region of the Church of Carthage, from the fourth to the sixth centuries. Donatists argued that Christian clergy must be faultless for their ministry to be effective and their prayers and sacraments to be valid. Donatism had its roots in the long-established Christian community of the Roman province Africa Proconsularis (present-day Tunisia, the northeast of Algeria, and the western coast of Libya) and Mauretania Tingitana (roughly with the northern part of present-day Morocco), in the persecutions of Christians under Diocletian.
Branch theoryBranch theory is an ecclesiological proposition that the One, Holy, Catholic, and Apostolic Church includes various different Christian denominations whether in formal communion or not. The theory is often incorporated in the Protestant notion of an invisible Christian Church structure binding them together. Anglican proponents of Anglo-Catholic churchmanship who support the theory include only the Roman Catholic, Eastern Orthodox, Oriental Orthodox, Scandinavian Lutheran, Old Catholic, Moravian, Persian and Anglican churches as branches.
