About 650 senior members of the Anglican clergy from around the world are gathering in Canterbury for the Lambeth Conference.
Dr Rowan Williams invites senior clergy to the conference
The conference is pivotal in helping unify the largest Protestant Church grouping in the world, but this year it comes at a time of rifts over key issues affecting the Anglican Communion.
WHAT IS THE PURPOSE OF THE LAMBETH CONFERENCE?
The conference is the only meeting of all the archbishops and bishops of the Anglican Communion - the family of Churches around the world.
The Archbishop of Canterbury calls the conference once every 10 years to bring those Churches together.
Senior members of the clergy worship and study together during the conference and it provides a forum for debate on key issues affecting the Anglican Communion.
The Archbishop of Canterbury, Dr Rowan Williams, says on the conference's website: "The chief aims of our time together are, first, that we become more confident in our Anglican identity, by deepening our awareness of how we are responsible to and for each other; and second, that we grow in energy and enthusiasms for our task of leading the work of mission in our Church."
But about 200 bishops have declined his invitation to the conference.
Delegates do not have to say why they have declined their invitations.
But some plan to boycott the meeting because they have been angered by what they see as the Bible's teaching on homosexuality being ignored.
WHERE DOES THE LAMBETH CONFERENCE GET ITS NAME?
The conference gets its name from Lambeth Palace, the Archbishop of Canterbury's residence in London, where the conference used to be held.
It first took place there in 1867 and was attended by just 76 bishops. This year's conference, at the University of Kent, is the 14th. It is not open to the public.
WHERE IN THE WORLD ARE THE DELEGATES FROM?
Archbishops and bishops from 160 countries will be attending the conference, but no delegates from Nigeria, Uganda and Rwanda are coming.
Senior bishops and archbishops from Churches within the Anglican Communion are joined by bishops from other Churches "in communion" with the Anglican Communion such as the Churches of Bangladesh, North and South India, and Pakistan.
A number of ecumenical guests are also invited. It is up to the archbishop whom he invites.
Spouses of the bishops who attend are invited by the Archbishop of Canterbury's wife to a spouses' conference.
WHAT ARE THE KEY ISSUES THAT WILL DOMINATE?
This year's conference will attempt to begin to heal the rifts within the Anglican Communion over contentious issues, including women bishops and the sexuality of the clergy.
Ahead of the conference, a coalition of Anglican traditionalists challenged the authority of the Archbishop of Canterbury. At a meeting in Jerusalem, the Global Anglican Future Conference (Gafcon) vowed to combat modern trends in the Church, including the ordination of gay members of the clergy.
The decision of the Church of England's General Synod earlier this month to ordain women bishops also sparked fury among some members of the clergy.
So sexuality and gender of clergy are likely to be among the topics that dominate debate during the 20-day conference.
Anglicans differ on how they believe the Bible should be interpreted, for example, whether it should be read as classing active homosexuality as a sin.
A number of bishops from around the world intend to boycott the Lambeth Conference in protest at the presence of others who support the ordination of gay members of the clergy.
This comes after a total of 250 bishops attended the rival Gafcon meeting in Jerusalem.
Here they vowed to set up a council of bishops to restore order within the worldwide Anglican Church.
The rift has been widening since the ordination of the gay Bishop of New Hampshire, the Right Reverend Gene Robinson, in 2003.
The role of the bishops' leadership in the Church is tabled as a key topic for this year's conference.
But the role of women bishops in particular is likely to be a contentious issue after the General Synod vote.
Some 1,300 clergy had threatened to leave the Church of England if their concessions were not met.
While safeguards to traditionalists were not offered in the vote, it was agreed a code of practice would be drawn up. The first consecration of a woman bishop is years away.
The Roman Catholic Church, which does not ordain women, has already warned the Church of England that this decision on women bishops will hamper relations between the churches.
Conversion of other faiths
There is a range of views as to what extent Anglican Churches should seek to convert other faiths.
The Church in Africa is experiencing huge growth - in Muslim countries among others.
Some believe there is a Biblical mandate to go out and convert other faiths, while other more liberal wings of the Church do not feel this is as necessary.
On the agenda at the conference are topics on evangelism and how to engage in a multi-faith world so these are likely to provide opportunity to discuss the issue.
CAN THE LAMBETH CONFERENCE UNITE THE ANGLICAN COMMUNION?
The conference will conclude with attempts to get the delegates from Churches across the world to sign up to a covenant calling for an agreement on central beliefs - including an end to the ordination of gay bishops and same sex blessings in church - and discipline in following them.
But this would be unacceptable to the American Church, and liberals elsewhere in the Communion, including the Church of England.