The theological premise upon which any concept of reunion is founded is that the visible church of God on earth is properly, or at its best, or archetypally, a single entity-a body, or an organism. The concept will be opaque wherever Christians hold either that the only proper unity of the church is invisible (and eschatological) and thus indivisible, or that the given oneness of the visible church (e.g., in and by baptism) is totally indivisible. On either of these views the church is a union which cannot be broken and thus does not admit of reuniting. The former view is characteristic of classical independency or Brethrenism, the latter of twentieth- century ecumenists rationalizing their failures.

In 1 Corinthians Paul seems to indicate that, while it was theologically unthinkable and virtually immoral for division to enter into the body, yet it was in fact not only possible but actually happening. It was the harmony and true oneness of the local “body” which was endangered, and Paul does not allocate blame separately to either party, but simply appeals to them to belong and live with each other, acknowledging no “party leaders” lower than Christ.

The post-apostolic church, in various ways, had to make more sophisticated appeals than this. The existing institution had prior claims to be “the church” and those who separated themselves had to return to that unity. The true church was identifiable to Ignatius, Irenaeus, Cyprian, and their contemporaries as those who held the true faith and were joined to a true bishop; the difficulty was that in disputes there were no higher courts of appeal to decide who had the true faith and which bishops were true ones. The true church had in the last resort to be self-authenticating to its members, and if more than one organization was thus self-authenticating, then sheer weight of numbers or the secular power (as with Augustine and the Donatists) had to settle it.

In the early centuries this concept of the single universal body of the church meant that reunion had to come through individual seceders or schismatics returning into union. What it could not mean was that two equal and mutually respecting denominations merged, with each making its contribution to the future. A schismatic returning had to renounce all that he had known and done while in schism; he reunited by submitting. Augustine of Hippo* made one small step toward the Donatists* when he afforded recognition to baptisms and orders given in schism, but this was novel-and perhaps ultimately misleading also in terms of Augustine's own ecclesiology. It gave some first shadow of respectability to reunion in that it allowed certain ecclesial marks to the Donatists.

The major schism of the church in the centuries following was that between East and West, formalized in 1054, but probably inevitable from long before that. At this point the theological thinking of each part about the other became obscure. There was an uncertain claim (coming down to the present day) on each side that it alone was the true church to which submission was required from the other. But it was uncertain, and each side retained at least some concept that the schism needed to be “healed” by something less than total surrender by the other. Attempts were occasionally made toward reconciliation, the Council of Florence* (1438-39) being the most notable.

The Reformation* brought new ecclesiologies in its train, and new concepts of the unity of the church in consequence. The Reformers took the view that Rome had left the truth, to which they clung, and therefore the guilt of schism and the duty to “return” lay with the pope. They differed as to whether Rome still exhibited the marks of the Christian Church at all, and they were far more concerned to protect themselves from her than to promote reunion with her. Their view of their own churches was broadly cuius regio eius religio, and this left them with no constitutional duties to each other except a fraternal strengthening of each other's hands. Finally they showed various degrees of tolerance to dissenters who arose within their parishes or districts, but the tolerance was rarely more than grudging, and in England the persecution of the Puritans* (as under Whitgift* and Bancroft*) became almost fanatical. There never existed two or more bodies which could face each other with mutual understanding and sympathy, and seek to unite with each other. The Hampton Court* and Savoy* conferences (1604 and 1661) from this standpoint were parodies of conferences-however they were occasioned, they quickly became mere instruments of triumphalist policy by the ruling (i.e., Anglican or Episcopalian) party. A greater possibility emerged in 1689 when the two parties had worked together in the overthrow of James II,* but the upshot was not a comprehensive united church (as many had hoped), but a wider tolerance for a multiplicity of churches.

A rare and interesting variant on these moves was found in the early part of the eighteenth century when Archbishop Wake* corresponded for some time (1717-19) with Du Pin, a Roman Catholic theologian of the Sorbonne. The end in view was an Anglicanizing of the French Church away from the new Ultramontanism* until the Churches of England and France could meet in a fraternal unity. More bizarre was the temporary flirtation of the English Nonjurors* with Eastern Orthodoxy.

The eighteenth century in England itself saw the Evangelical Revival. This led to the building of Methodist chapels alongside parish churches throughout the land, and fixed a deep division between the two-a division which was cultural and sociological as well as theological, a prime instance of the part “nontheological” factors play in the keeping of Christians separate from each other. The problem was now exactly that to which 1 Corinthians had been addressed, that of rival denominations cheek-by-jowl with each other. No attempt was made at reunion once John Wesley* had died, and the Oxford Movement* added the impression of a strong theological division to justify the already existing separation. England was a very powerful force in the nineteenth-century missionary expansion, so that the English divisions reproduced themselves around the world, with the further complications added of Lutheranism, Presbyterianism, and Moravianism from the Continent.

In the twentieth century the ecumenical movement has spawned or strengthened moves to corporate reunion throughout the world. Mention can be made of Scottish Presbyterian unions in 1900 and 1929, English Methodist union in 1932, and Presbyterian- Congregationalist union in 1972, and the formation of the United Church of Canada.* Anglicans were involved in the Church of South India* in 1947 and in the Churches of North India* and Pakistan* in 1970, in company with six other denominations. Many other unions have been projected but a number not implemented, including schemes in the USA, between Anglicans and Methodists in England (finally defeated in 1972), in Nigeria, East Africa, Australia, and New Zealand.

In all these moves neither the Roman Catholic Church nor the evangelical independent churches have been involved, due to their ecclesiologies and traditions. A stage is now arriving where Roman Catholics can and do become very sympathetic “observers” in schemes between other churches, but they have no mandate to negotiate toward local or national unions. There has at the same time arisen among those most in favor of reunion an impatience, or at least an ennui, concerning the whole concept of schemes for reunion. There is a proneness to trace the rise of antiinstitutional Christianity to the preoccupation with institutions which has marked the schemes of recent years. Thus in the early 1970s the specific schemes for reunion which have been projected but not yet implemented lie somewhat under a cloud, with the question arising as to whether institutional Christianity has not more important items on its agenda.

S.L. Ollard, Reunion (1919); A.C. Headlam, The Doctrine of the Church and Christian Reunion (1920); G.K.A. Bell (ed.), Documents on Christian Unity (3 vols., 1924-48): covers 1920- 48; K.D. Mackenzie (ed.), Union of Christendom (1938); J.D. Murch, Cooperation Without Compromise (1956); S.C. Neill, The Church and Christian Union (1968). See also under Ecumenical Movement and World Council of Churches.