LONDON — The head of the Church of England is leaving office Monday after a decade as the spiritual leader of the world's 80 million-strong Anglican Communion.

Rowan Williams, the 104th Archbishop of Canterbury, will be replaced by 56-year-old former oil executive Justin Welby, the Bishop of Durham.

The 10 years in which the 62-year-old Williams held office saw him struggling to maintain unity within the Anglican Communion amid bitter disagreements over female bishops and church teachings on gay relationships.

Williams has been praised for engaging with church critics and atheists including Richard Dawkins, but he has also raised eyebrows with his opinions on controversial issues including the war in Iraq and shariah law.

Williams will step down Monday to start a new role as Master of Cambridge University's Magdalene College.