Archbishop of Canterbury Dr Rowan Williams will step down from his position as the head of the Anglican church in December.
The 61-year-old church leader, who in 2010 came close to splitting over the ordination of gay clergy and women bishops, has said in a statement on his website that standing down was not an easy decision.
Williams was appointed Archbishop of Canterbury in 2002 and will take the position of Master of Magdalene College at Cambridge University in January.
His departure comes after tensions within the Anglican Communion over the issue of homosexuality and women bishops.
The Church of England is now at the forefront of a campaign to try to stop moves towards gay marriage in Britain, although Williams himself has not been leading on that subject.
During his time as Britain's senior bishop, Williams said he was not 'positive' about gay bishops having relationships.
'There's no problem about a gay person who's a bishop,' he said in an interview, reported in The Telegraph.
'It's about the fact that there are traditionally, historically, standards that the clergy are expected to observe.'
Asked what was wrong with a homosexual bishop having a partner, he added: 'I think because the scriptural and traditional approach to this doesn't give much ground for being positive about it.'
He told The Times Magazine that even discussing the difficult topic could lead to the persecution of homosexuals in countries like Uganda, by fuelling intolerance.
Williams said the worst part of the job has been struggling with long-running conflicts in the church.
He said: 'The worst aspects of the job, I think, have been the sense that there are some conflicts that won't go away, however long you struggle with them, and that not everybody in the Anglican Communion or even in the Church of England is eager to avoid schism or separation.
'But I certainly regard it as a real priority to try and keep people in relationship with each other.'
In his statement today (16 March), he said: 'It has been an immense privilege to serve as Archbishop of Canterbury over the past decade.
'During the time remaining there is much to do, and I ask your prayers and support in this period and beyond.'
The Crown Nominations Commission (CNC) will consider 'in due course' the selection of a successor.