Vicar of Christ
Vicar of Christ (from Latin Vicarius Christi) is a term used in different ways, with different theological connotations throughout history. As the original notion a vicar is of "earthly representative of God or Christ" but also used in sense of "person acting as parish priest in place of a real parson" The title is now used in Catholicism to refer to the bishops and more specifically to the Bishop of Rome (the pope).
History and different uses 
During the history of Christianity, the title of Vicar of Christ was used in different ways, with implications for theological, pastoral or different time.
Use for the bishops 
The first record of the concept of the Vicar of Christ is mentioned in the Epistle to the Magnesians of St. Ignatius, Bishop of Antioch, a disciple of St. John, probably commanded by Peter, with a pastoral sense, written between the years 88 and 107 AD "your bishop presides in the place of God (...)". Although Ignatius did not explicitly use the term Vicar of Christ, he clearly sets out the concept. More recently, the Second Vatican Council's Dogmatic Constitution on the Church Lumen gentium noted that bishops are "vicars and ambassadors of Christ," and the Catechism of the Catholic Church notes that each bishop governs his diocese "[a]s Christ's vicar."
Use for the Holy Spirit 
The second recorded use of the term "Vicar of Christ" is found in the epistles of Tertullian in the 3rd century, with a different theological slant to refer to the Holy Spirit, that is, as Christ is not physically performing miracles in the Church, Holy Spirit acts as his Vicar on his behalf, performing miracles and preventing the Church err. It is unknown whether this term was widely used in the early Church, or whether it was a personal theological observation of Tertullian.
Use for the popes 
The third use of the term Vicar of Christ appears in the 5th century, in a synod of bishops to refer to Pope Gelasius I. The theological connotations of the title got a pastoral sense, evoking the words of Christ to the Apostle Peter, regarded by the first Catholic Pope in John 21:16-17, "Feed my lambs... Feed my sheep", so Christ made Peter his vicar and pastor with the responsibility to feed his flock (i.e. the Church) in his own place.
However, the use of the title to refer to the popes in the early Church was unstable, and several variants of the use of Vicar were used for the Pope, as "Vicar of Peter", indicating that they were the successors of St. Peter, "Vicar of the Prince of the Apostles" or "Vicar of the Apostolic See", among other variants. This title is used by the Roman Missal in their prayers for a dead pope, and the oath of allegiance to St. Boniface to Pope Gregory II. Since 1200, Popes have consistently used this title. Insisting that he - and he alone - had the right to remove bishops from office, Pope Innocent III appealed to the title of Vicar of Christ. (cap. "Inter corporalia", 2, "De trans. ep.") Occasionally, Popes like Nicholas III used "Vicar of God" as an equivalent title) The 2012 edition of the Annuario Pontificio gives "Vicar of Jesus Christ" as the second official title of the Pope (the first being "Bishop of Rome").
Use in Cesaropapism 
Another use of the title, with a different meaning, appeared in the Eastern Churches, in use between the century fifth and sixth, the term was used to refer to the Byzantine emperor, showing the apex of caesaropapism. Though decisions on doctrine, liturgy and spirituality were left to the bishops, the Emperor had tremendous influence on the church.
Conspiracy theories 
The conspiracy theory of "Vicarius Filii Dei" (Vicar of the Son of God), supposedly considered an expansion of the historic title "Vicarius Christi", is a term used in the spurious "Donation of Constantine" to refer to Saint Peter. From the 19th century, because the interpretation of Uriah Smith, some groups of Seventh-day Adventists argue that the sentence is identified with the "number of the beast" (666), and would be used in the [papal tiara], calling the Pope would be the Antichrist. But due to lack of images or any source of Use "Vicarius Filii Dei" the tiara or mitre, and the term was never used as an official title (as well as the fact that their founder Ellen Gould White's name also adds up to 666 by the same system), the claim was abandoned by many Seventh-day Adventists.
- Online Etymology Dictionary - Vicar
- "Second Vatican Council, Dogmatic Constitution on the Church Lumen gentium § 27". Site da Santa Sé. Retrieved 2010-01-27.
- "Vicar of Christ". Catholic Encyclopedia; New Advent. Retrieved 2010-01-27.
- RAY, Stephen. Upon this Rock. San Francisco, CA: Ignatius Press, 1999. p.119.
- "The Epistle of Ignatius to the Magnesians (2, 6:1)". Catholic Encyclopedia; New Advent. Retrieved 2010-01-27.
- "Catechism of the Catholic Church ¶ 1560". Site da Santa Sé. Retrieved 2012-12-04.
- "Prescription against Heretics (Chapter 28)". Catholic Encyclopedia; New Advent. Retrieved 2010-01-27.
- "On the Veiling of Virgins (Chapter 1)". Catholic Encyclopedia; New Advent. Retrieved 2010-01-27.
- "Liturgical Notes and Resource Materials for Use upon the Death of a Pope". Retrieved 2010-01-27.
- "Promessa de Fidelidade de São Bonifácio ao Papa Gregório II, por ocasião de sua sagração episcopal". Site Montfort. Retrieved 2010-01-28.
- New commentary on the Code of Canon Law. Retrieved 2010-01-27.
- Annuario Pontificio, published annually by Libreria Editrice Vaticana, edition of 2012 (ISBN 978-88-209-8722-0), p. 23*.
- Richards, Jeffrey. The Popes and the Papacy in the Early Middle Ages 476–752 (London: Routledge & Kegan Paul, 1979) pp. 14–15-16.
- Uriah Smith, The United States in the Light of Prophecy. Battle Creek, Michigan: Seventh-day Adventist Publishing Association (1884), 4th edition, p.224,
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- Seventh-day Adventist Bible Commentary, vol. 11, p. 223.
- Adult Sabbath School Lesson for April–June 2002. See lesson 10 (June 1–7), "The Dragon Versus the Remnant Part 2"; particularly the studies for Thursday and Friday
- "ENDTIME ISSUES NEWSLETTER No. 145 "Armageddon and ‘the War on Terror’: Part II"". Retrieved 2010-01-27.
- "ENDTIME ISSUES NEWSLETTER NUMBER 146 "The Saga of the Adventist Papal Tiara: Part 2"". Retrieved 2010-01-27.