A bishop is an ordained person who holds a specific position of authority in any of a number of Christian churches.
The bishop's role is typically called the "episcopacy", because the word "bishop" is derived ultimately from the Greek word episkopos (επισκοπος), which literally means overseer. Episkopos is used in the New Testament in the epistle of St Paul to Timothy 3:1-7 and Paul's epistle to Titus 1:5-9, which contains a description for the bishop's qualifications and duties. The bishop's stated duties entail administration; the bishop is described as the "steward of God." (Titus 1:7, KJV) Those duties also include teaching; the bishop is enjoined to "hold fast the faithful word, as he hath been taught, that he may be able by sound doctrine both to exhort and to convince the gainsayers." (Titus 1:9)
The bishop must be even-tempered, sober, just, holy, and temperate; he should not be a novice Christian. A bishop is expected to rule his own house well, "having all his children in subjection with all gravity." He should be the "husband of (only) one wife." Whether this enjoins a bishop to have never been remarried, requires a bishop to be married, or simply disqualifies a candidate who practices polygamy are questions of interpretation about which there are several opinions. At this stage in the history of Christianity, bishops were permitted to marry and have children.
The bishops are also mentioned in the Acts of the Apostles 20:28, in which they are described as "shepherds". In Latin, a shepherd is a pastor. To refer to a member of the Christian clergy as "pastor" refers to the image of the bishop as shepherd of his "flock." The passage in Acts seems to view the office of bishop as referring to the same office as the "elders."
"Elders," "presbyters," or "priests" --- translations differ --- are also mentioned in the Epistle to Titus, in a manner that makes it difficult to determine whether a separate level of hierarchy above or below the bishop is intended; it seems that here the words are synonyms also. The Epistle to Timothy mentions deacons in a manner that indicates more clearly that the office of deacon differs from the office of the bishop, and is subordinate to it, though it carries similar qualifications.
Bishops of the Church of England still sit as peers[?] in the House of Lords in Great Britain, as representatives of the established church. In France before the French Revolution, representatives of the clergy --- in practice, bishops and abbots of the largest monasteries --- comprised one of the three Estates in the Estates-General, until their role was abolished during the French Revolution
A number of bishops served as Electors in the Holy Roman Empire. By the terms of the Golden Bull of 1356. the Bishops of Mainz, Trier, and Cologne were made permanent electors who chose the next Emperor upon the death of his predecessor. The bishop of Mainz was, in fact, the head of the electors. As electors of the Holy Roman Empire, these bishops were sovereigns in their own right, and governed their dioceses in civil as well as ecclesiastical matters. By virtue of their electorates, the bishop of Mainz held the office of the High Chancellor of Germany; Cologne was High Chancellor of Italy, and Trier was High Chancellor of Burgundy.
But, of course, the highest prince bishop is the Pope, who ruled as monarch of the Papal States by virtue of his title as Bishop of Rome. His claim to this fief rested on the forged Donation of Constantine, but in fact his authority over this kingdom in central Italy grew slowly after the collapse of Roman and Byzantine authority in the area. The Papal States were abolished when King Victor Emmanuel II took possession of Rome in 1870 and completed the reunification of Italy. This became a perennial source of tension between the Papacy and the government of Italy. In 1929, Pope Pius XI made a deal with the Fascist government of Benito Mussolini and became the monarch of the Vatican, and he was recognised as an independent monarch by the Lateran Treaties, a throne the current Pope continues to enjoy.
Bishops are especially prominent among the leadership of the Roman Catholic church, the Eastern Orthodox Church, Oriental Orthodox Church, and Anglican church. Bishops are generally responsible for leading a large or heavily-populated area (a diocese) and all the churches contained therein. An archbishop is a bishop in charge of an important diocese; however, an archbishop does not hold a higher rank than any other bishop. The Pope, in addition to being the leader of the Roman Catholic church, is the Bishop of Rome. Each bishop within Roman Catholicism is not answerable to his fellow bishops collectively; each diocese is independent and only answerable directly to the pope.
A bishop can be ordained only by a minimum of two other bishops. Only a bishop may ordain a priest. A priest may celebrate the Divine Liturgy or Mass only with the blessing of a bishop; typically, an antimension signed by the bishop is kept on the altar partly as a reminder of whose altar it is and under whose omophorion the priest at a local parish is serving. In the sanctuary or altar area is typically a "bishop's throne" for the bishop. (The antimension is the rectangular piece of cloth, of linen or silk, with representations of the entombment of Christ, the four evangelists, and scriptural passages related to the eucharist. The antimension must be consecrated by the bishop of a church. No sacrament of the church is valid without one, as it indicates the authority of the bishop or literally "instead of the table". It often has a very small relic sewn into it. The omophorion is one of the bishop's vestments, made of a band of brocade worn about the neck and around the shoulders. It signifies the Good Shepherd by symbolizing the lost sheep that is found and thrown over the shoulders of the shepherd. The omophorion is a symbol of the spiritual authority of a bishop.)
Catholic, Anglican, Eastern Orthodox, and Oriental Orthodox bishops claim to be part of a continuous sequence of ordained bishops since the days of the apostles, the apostolic succession. However, since a bull of Pope Leo XIII issued in 1896, the Roman Catholic church has insisted that Anglican orders are invalid, because of that church's changes in the ordination rites. The Roman Catholic church does however recognize as valid (though illegal) ordinations done by breakaway Roman Catholic bishops, and groups descended from them, so long as the people receiving the ordination conform to other canonical requirements; this gives rise to the phenomenon of episcopi vagantes.
Some other churches (such as Lutherans, Methodists and the Church of Jesus Christ of Latter-day Saints (LDS)) also have bishops, but their roles differ significantly from the Catholic and Anglican ones.
In the United Methodist Church, bishops are administrative superintendents of the church; they are elected from among the clergy by vote of the clergy in regional conferences. United Methodist bishops serve for four year terms, and may serve up to three terms. John Wesley made Thomas Coke[?] and Francis Asbury bishops for the United States of America in 1784, where Methodism first became a separate denomination apart from the Church of England. Methodists in Great Britain acquired their own bishops early in the nineteenth century, after the Methodist movement in Britain formally parted company with the Church of England.
LDS bishops claim apostolic succession, although they define it somewhat differently; see priesthood and apostolic succession for details. Lutheran and Methodist bishops do not claim apostolic succession, except in the Church of Sweden and the Church of Finland.