Ecclesiology, polity and ethos
The Anglican Communion has no official legal existence nor any governing structure which might exercise authority over the member churches. There is an Anglican Communion Office in London, under the aegis of the Archbishop of Canterbury, but it only serves in a supporting and organisational role. The communion is held together by a shared history, expressed in its ecclesiology, polity and ethos and also by participation in international consultative bodies.
Three elements have been important in holding the communion together: first, the shared ecclesial structure of the component churches, manifested in an episcopal polity maintained through the apostolic succession of bishops and synodical government; second, the principle of belief expressed in worship, investing importance in approved prayer books and their rubrics; and third, the historical documents and the writings of early Anglican divines that have influenced the ethos of the communion.
Originally, the Church of England was self-contained and relied for its unity and identity on its own history, its traditional legal and episcopal structure and its status as an established church of the state. As such Anglicanism was, from the outset, a movement with an explicitly episcopal polity, a characteristic which has been vital in maintaining the unity of the communion by conveying the episcopate's role in manifesting visible catholicity and ecumenism.
Early in its development, Anglicanism developed a vernacular prayer book, called the Book of Common Prayer. Unlike other traditions, Anglicanism has never been governed by a magisterium nor by appeal to one founding theologian, nor by an extra-credal summary of doctrine (such as the Westminster Confession of the Presbyterian churches). Instead, Anglicans have typically appealed to the Book of Common Prayer (1662) and its offshoots as a guide to Anglican theology and practise. This had the effect of inculcating the principle of lex orandi, lex credendi (Latin loosely translated as "the law of praying [is] the law of believing") as the foundation of Anglican identity and confession.
Protracted conflict through the 17th century with radical Protestants on the one hand and Catholics who recognised the primacy of the Pope on the other, resulted in an association of churches that were both deliberately vague about doctrinal principles, yet bold in developing parameters of acceptable deviation. These parameters were most clearly articulated in the various rubrics of the successive prayer books, as well as the Thirty-Nine Articles of Religion (1563). These articles have historically shaped and continue to direct the ethos of the communion, an ethos reinforced by their interpretation and expansion by such influential early theologians such as Richard Hooker, Lancelot Andrewes and John Cosin.
With the expansion of the British Empire, and hence the growth of Anglicanism outside Great Britain and Ireland, the communion sought to establish new vehicles of unity. The first major expression of this were the Lambeth Conferences of the communion's bishops, first convened in 1867 by Charles Longley, the Archbishop of Canterbury. From the beginning, these were not intended to displace the autonomy of the emerging provinces of the communion, but to "discuss matters of practical interest, and pronounce what we deem expedient in resolutions which may serve as safe guides to future action."