With the exception of the Roman Catholic and the Orthodox Catholic Churches, most churches make no moral distinction between rhythm and mechanical or chemical contraceptives, allowing the couple free choice.

Some Eastern Orthodox Churches have issued statements to the effect that Anglican orders could be accepted, yet have still reordained former Anglican clergy ; other Orthodox churches have rejected Anglican orders altogether.

As they do not receive Holy Orders in the Catholic, Orthodox and Oriental Churches, they do not possess the ability to ordain any religious to Holy Orders, or even admit their members to the non-ordained ministries to which they can be installed by the ordained clergy ( females do not serve as clergy anyway, per formal church teaching, in these churches ), nor do they exercise the authority they do possess under canon law over any territories outside of their monastery and its territory ( though non-cloistered, non-contemplative female religious members who are based in a convent or monastery but who participate in external affairs may assist as needed by the diocesan bishop and local secular clergy and laity, in certain pastoral ministries and administrative and non-administrative functions not requiring ordained ministry or status as a male cleric in those churches or programs ).

The lack of apostolic succession through bishops is the primary basis on which Protestant communities are not considered churches by the Orthodox churches and the Roman Catholic Church.

Some Protestants feel that such claims of apostolic succession are proven false by the differences in traditions and doctrines between these churches: Roman Catholics and Eastern Orthodox consider both the Church of the East and the Oriental Orthodox churches to be heretical, having been anathematized in the early ecumenical councils of Ephesus ( 431 ) and Chalcedon ( 451 ) respectively.

Present-day Christian religious bodies known for conducting their worship services without musical accompaniment include some Presbyterian churches devoted to the regulative principle of worship, Old Regular Baptists, Primitive Baptists, Plymouth Brethren, Churches of Christ, the Old German Baptist Brethren, the Eastern Orthodox Christian Church and the Amish, Old Order Mennonites and Conservative Mennonites.

He is venerated by the Roman Catholic Church, Oriental and Eastern Orthodox churches, the Lutherans, and the Anglican Communion.

The following is a troparion ( hymn ) to St Athanasius sung in some Eastern Orthodox churches.

He is celebrated in many churches on his feast days: 30 January in the Old-Calendar Eastern Orthodox Church and the Coptic Orthodox Church ; 17 January in the New-Calendar Eastern Orthodox Church, the Bulgarian Orthodox Church, the Roman Catholic Church and the Coptic Catholic Church.

He is regarded as the " first master of the desert and the pinnacle of holy monks ", however, and there are monastic communities of the Maronite, Chaldean, and Orthodox churches which state that they follow his monastic rule.

The Books of the Bible are listed differently in the canons of Judaism and the Catholic, Protestant, Greek Orthodox, Slavonic Orthodox, Coptic, Georgian Orthodox, Armenian Apostolic, Syriac, Ethiopian and Eritrean Orthodox churches, although there is substantial overlap.

The Eastern Orthodox, Oriental Orthodox and Eastern Catholic churches may have minor differences in their lists of accepted books.

He has no direct jurisdiction over the other patriarchs or the other autocephalous Orthodox churches, but he, alone among his fellow-primates, enjoys the right of convening extraordinary synods consisting of them and / or their delegates to deal with ad hoc situations and has also convened well-attended Pan-Orthodox Synods in the last forty years.

Synods in Eastern Rite Catholic Churches are similar to synods in Orthodox churches in that they are the primary vehicle for election of bishops and establishment of inter-diocesan ecclesiastical laws.

However, metropolitans ( archbishops in the Greek Orthodox Church ) are the chairmen of their respective synods of bishops, and have special privileges.

Three Orthodox synods ruled against him and in Palamas's favor ( two " Councils of Sophia " in June and August 1341, and a " Council of Blachernae " in 1351 ).

He has no direct jurisdiction over the other patriarchs or the other autocephalous Orthodox churches and cannot interfere in the election of bishops in autocephalous churches but he alone enjoys the right of convening extraordinary synods consisting of them and / or their delegates to deal with ad hoc situations and has also convened well-attended Pan-Orthodox Synods in the last forty years.

The Orthodox have synods where the highest authorities in each Church community are brought together, but unlike Roman Catholicism no central individual or figure has the absolute and infallible last word on church doctrine.

As archbishop he restored the Byzantine churches ; issued a catechism to the clergy with instructions that it should be learned by heart ; composed rules for the priestly life, entrusting to the deacons the task of superintending their observance ; assembled synods in various towns in the dioceses, and firmly opposed the Polish Imperial Chancellor Sapieha, when he wished to make many concessions in favour of the Eastern Orthodox.

Further, proponents of the necessity of the personal apostolic succession of bishops within the Church point to the universal practice of the undivided early Church ( up to AD 431 ), before being divided into the Church of the East, Oriental Orthodoxy, the Eastern Orthodox Church and the Roman Catholic Church.

Roman Catholics recognize the validity of the apostolic successions of the bishops, and therefore the rest of the clergy, of the Eastern Orthodox, Oriental Orthodox, Church of the East, and the Old Catholic Church ( Union of Utrecht only ).

Within the Catholic Church, Eastern Orthodox, Oriental Orthodox, Anglican, Old Catholic, Independent Catholic Churches, and in the Assyrian Church of the East, bishops claim apostolic succession, a direct historical lineage dating back to the original Twelve Apostles.

Eastern Orthodox bishops, along with all other members of the clergy, are canonically forbidden to hold political office.

Most Eastern Orthodox churches allow varying amounts of formalised laity and / or lower clergy influence on the choice of bishops.

Catholic, Orthodox, Anglican, Old Catholic and some Lutheran bishops ( for example, Sweden ) claim to be part of the continuous sequence of ordained bishops since the days of the apostles referred to as apostolic succession.

Orthodoxy considers apostolic succession to exist only within the Universal Church, and not through any authority held by individual bishops ; thus, if a bishop ordains someone to serve outside of the ( Orthodox ) Church, the ceremony is ineffectual, and no ordination has taken place regardless of the ritual used or the ordaining prelate's position within the Orthodox Churches.

The arms of Oriental Orthodox bishops will display the episcopal insignia ( mitre or turban ) specific to their own liturgical traditions.

In the Catholic, Orthodox and Oriental Orthodox traditions, bishops are required to be celibate.

Furthermore, the Eritrean Orthodox Tewahedo Church similarly became independent of the Ethiopian Tewahedo Church in 1994, when four bishops were consecrated by Pope Shenouda III of Alexandria to form the basis of a local Holy Synod of the Eritrean Church.

Other Christian churches also laying claim to the description " Catholic " include the Eastern Orthodox Church and those churches possessing the historic episcopate ( bishops ), such as those of the Anglican Communion.

After the East-West Schism, conventionally dated to 1054, a brief reunification was agreed to between the Pope and a number of Eastern Orthodox bishops at the Council of Florence.

However, this agreement was denied by one of the Orthodox bishops present, namely Mark of Ephesus, and the common people of the Orthodox churches generally rejected the agreement as well.

An Orthodox congress of Eastern Orthodox bishops met in Constantinople in 1923 under the presidency of Patriarch Meletios IV, where the bishops agreed to the Revised Julian calendar.

Both the Eastern Orthodox Church and Roman Catholic Church recognise as ecumenical the first seven councils, held from the 4th to the 9th century ; but while the Eastern Orthodox Church accepts no later council or synod as ecumenical, the Roman Catholic Church continues to hold general councils of the bishops in full communion with the Pope, reckoning them as ecumenical, and counting in all, including the seven recognized by the Eastern Orthodox Church, twenty-one to date.

Anglican clergy who join the Orthodox Church are reordained ; but Orthodox Churches hold that if Anglicanism and Orthodoxy were to reach full unity in the faith, perhaps such reordination might not be found necessary.

In the Orthodox Church, only actual monastics are permitted to be elevated to the rank of Archimandrite.

Normally there are no celibate priests who are not monastics in the Orthodox Church, with the exception of married priests who have been widowed.

Arianism is defined as those teachings attributed to Arius which are in opposition to mainstream Trinitarian Christological doctrine, as determined by the first two Ecumenical Councils and currently maintained by the Roman Catholic Church, the Eastern Orthodox Churches, the Oriental Orthodox Churches, and most Reformation Protestant Churches.

The Catholic and Orthodox Churches consider invalid as a sacrament the administration of Anointing of the Sick by such chaplains, who in the eyes of those Churches are not validly ordained priests.

The Roman Catholic and Eastern Orthodox receive several additional books in to their canons based upon their presence in manuscripts of the ancient translation of the Old Testament in to Greek, the Septuagint ( although some of these books, such as Sirach and Tobit, are now known to be extant in Hebrew or Aramaic originals, being found amongst the Dead Sea Scrolls ).

The spelling and names in both the 1609 – 1610 Douay Old Testament ( and in the 1582 Rheims New Testament ) and the 1749 revision by Bishop Challoner ( the edition currently in print used by many Catholics, and the source of traditional Catholic spellings in English ) and in the Septuagint ( an ancient translation of the Old Testament in to Greek, which is widely used by the Eastern Orthodox instead of the Masoretic text ) differ from those spellings and names used in modern editions which are derived from the Hebrew Masoretic text.

For the Orthodox canon, Septuagint titles are provided in parentheses when these differ from those editions.

The disputed books, included in one canon but not in others, are often called the Biblical apocrypha, a term that is sometimes used specifically ( and possibly pejoratively in English ) to describe the books in the Catholic and Orthodox canons that are absent from the Jewish Masoretic Text ( also called the Tanakh or Miqra ) and most modern Protestant Bibles.

; Catholicos: Catholicoi are the heads of some of the Eastern Orthodox, Oriental Orthodox, and Eastern Rite Catholic sui iuris churches ( notably the Armenian ), roughly similar to a Patriarch ( see above ).