London, England - The Archbishop of Canterbury Rowan Williams, spiritual leader of the Anglican Communion, who has long struggled to prevent a schism over women and gay bishops and same-sex unions, announced on Friday he will step down at the end of the year.
The 80-million-strong worldwide Communion has been threatened with division for several years, with reformists and conservatives failing to bend to his authority or attempts at consensus.
Williams, 61, the head of the Church of England, the Anglican mother church, will return to academia, taking up a role as Master of Magdalene College, a senior role at Cambridge University. He previously taught theology at Cambridge and Oxford universities.
The normal retirement age for Church of England bishops is 70.
Williams, who was appointed to the post in 2002, will step down at the end of December and take up his new role in January.
"It has been an immense privilege to serve as Archbishop of Canterbury over the past decade, and moving on has not been an easy decision," he said in a statement.
Williams, who conducted the marriage of Prince William and Catherine Middleton in London last April, will remain in place to preside over Queen Elizabeth's diamond jubilee, marking her 60 years on the throne.
The bookmakers' favorite to replace him is the Church of England's second most senior cleric, the Archbishop of York, John Sentamu, though there are some who are against his outspoken views at a sensitive time for the church.
Another in the running is the Bishop of London, Richard Chartres, a friend of Prince Charles. But his chances may have suffered over St Paul's Cathedral's botched handling of a four-month camp by the anti-capitalist movement Occupy London on its doorstep.
Williams gave no reason for his stepping down, but his tenure has come during some of the church's most turbulent times.
This is a busy year for the Church of England, with its parliament, or General Synod, set to vote in July on the consecration of women bishops, and a landmark Anglican agreement called the Covenant.
Williams has invested much personal authority in these issues but has suffered embarrassment in both.
He put forward a compromise on women bishops in an attempt to keep traditionalist Anglo-Catholics from taking up an offer from Pope Benedict to switch to Rome within an ordinariate.
It is still unclear what form this compromise will take, but it is more than likely the synod will vote for women bishops after the dioceses, or parishes, overwhelmingly said "yes".
The dioceses are at the moment voting on the Covenant, an initiative put forward by Williams in an attempt to prevent disputes between churches in North America and Africa over gay bishops and same-sex unions. But dioceses look set to vote it down.
Williams has warned that the Anglican Communion faced a "piece-by-piece dissolution" if member churches failed to undertake to avoid actions that upset others.