Rowan Williams, who is spending his final months as Archbishop of Canterbury, is the 104th man to have served in that role.
His retirement marks the end of more than 20 years as a bishop and archbishop.
Dr Williams will leave his post at the end of December in time to start a new role as Master of Magdalene College, Cambridge, in January.
His departure comes amid growing tensions within the Anglican Communion over the issue of homosexuality.
Under his stewardship, the worldwide Anglican community has come close to splitting over the ordination of gay clergy.
Within the Church of England, his term in office has been overshadowed by the row over whether women should be appointed as bishops.
But Dr Williams will also be remembered as a peacemaker who used his time in office to make an impact across the world.
His visit to Zimbabwe in October 2011 was widely commended after he openly criticised the human rights abuses of President Robert Mugabe's regime.
He has also been praised for his ability to engage publicly on difficult matters of religion, particularly with the atheist author Richard Dawkins.
The Archbishop has also been pivotal to national events, including the Royal Wedding at which he married the Duke and Duchess of Cambridge at Westminster Abbey in 2011.
In the past Dr Williams has attracted criticism for straying outside of the religious arena. His opposition to the Iraq war, his call for reparations for the slave trade and his stance on the environment have raised eyebrows among the political establishment.
In 2008 he provoked an outcry after saying the application of sharia law in England under certain circumstances was unavoidable.
He also said the killing of al-Qaeda leader Osama Bin Laden while unarmed had left "a very uncomfortable feeling".
Dr Williams also spoke out against the coalition government, saying it was committing Britain to "radical, long-term policies for which no-one voted".
Excelled at school
A fluent Welsh speaker, he was born in 1950 in Swansea, where his father was a mining engineer.
Young Rowan Williams excelled at school in every subject except one - he had a permanent note excusing him from sport.
He was keen on drama and starred in many productions at Dynevor Grammar School and later at Christ's College, Cambridge, where he studied theology.
He went to Oxford for his doctorate and lectured at Mirfield Theological College in Leeds before returning to Cambridge and Oxford where he was fast gaining a reputation as a formidable theologian.
In 1979 Dr Williams published his first book and at the age of 36 he became Oxford University's youngest professor.
From 1991 to 1999 he served as Bishop of Monmouth, before becoming Archbishop of Wales.
A clue to his outspoken nature came at his enthronement ceremony in February 2003, when he used his sermon to urge Christians to engage the world of politics.
Since then he has made clear his views on a range of issues. But it is within the Anglican Church that his views have stirred the greatest controversy.
Dr Williams has consistently supported the ordination of women and in 2005 backed moves to allow women to serve as bishops, to the consternation of conservative Anglicans.
Hundreds of disillusioned Anglicans are now joining a special section of the Catholic Church - the Ordinariate - which has been created specifically for them by Pope Benedict XVI in protest at the decision to ordain women as bishops.
But it is, above all, the issue of gay clergy which has caused the archbishop his biggest headache.
June 2003 saw the appointment of an openly gay bishop in Reading, Jeffrey John - an old friend of Dr Williams and like him an active member of the moderate Anglo-Catholic group Affirming Catholicism.
Initially Dr Williams raised no objections to the appointment, raising hackles among conservative church leaders in the UK and abroad.
As the row escalated, Jeffrey John withdrew from the post.
Two months later the rank and file of the Anglican Church in the United States voted to elect an openly gay bishop, Reverend Canon Gene Robinson of New Hampshire.
One African archbishop responded by saying: "The devil has entered our Church."
Try as he might Dr Williams failed to get traditionalist church leaders - mainly in Africa - to reconcile their differences with the liberal wing of the church in North America.
The issue has threatened to cause a schism in the worldwide Anglican Communion.
In 2007 Dr Williams walked into another storm when he suggested the nativity could have been "a legend".
The Catholic and Anglican churches feel that they must stand together against the threat of secularism and that they are stronger in cooperation than they would be divided.
Yet, despite a number of meetings with the Pope, Dr Williams has failed to reach any sort of meaningful rapprochement with the Roman Catholic church.
In April last year he was forced to apologise after saying the Catholic Church in Ireland had lost all credibility after the child abuse scandal.
His major problem rests with his unique position.
The broad nature of the Church, which includes Anglo-Catholics, evangelicals and liberals, means it is difficult for it to achieve unity on many controversial matters.
But unlike the Pope, he has no power to force any of the 38 Anglican archbishops to submit to his will.
In September 2012, in an interview with the Daily Telegraph, he said he had not done enough to stop a split over homosexual priests and said he felt he had "disappointed" both liberals and conservatives.
He also suggested the workload of the Archbishop of Canterbury was now too much for one man.
"I suspect it will be necessary, in the next 10 to 15 years, to think about how that load is spread; to think whether in addition to the Archbishop of Canterbury there needs to be some more presidential figure who can travel more readily," he told the Telegraph.
The lot of an Archbishop of Canterbury has never been an easy one.
Thomas a Becket was murdered. Others, most notably Thomas Cranmer, have met their end at the hands of the executioner.
Dr Williams is not in much danger of either of these - but his outspoken views have ensured his departure will be greeted with a mixture of sadness and glee.