Billy Graham, the hugely popular American evangelist and one of the most influential Christian preachers of the 20th Century, has died at the age of 99.

Graham became one of the best-known modern-day promoters of Christianity in the world, preaching to audiences in large arenas, starting in London in 1954.

Over 60 years of preaching, he is estimated to have addressed some 210 million people.

Having been sceptical of the civil rights movement at home in the US, Graham went on to become an advocate of it in the 1950s.

After hearing a travelling evangelist at the age of 16, he became a committed Christian, and was ordained a minister in 1939.

Graham retired to his mountain home at Montreat, North Carolina, in 2005 after nearly six decades on the road and calling people to Christ.

His final New York City tour in 2005 was sponsored by 1,400 regional churches from 82 denominations.

As well as preaching to millions, Graham formed what some say was a close friendship with Queen Elizabeth II and met with 12 US presidents. When Bill Clinton's affair with Monica Lewinsky came to light, Graham called for forgiveness. Clinton told The New Yorker: 'He took sin seriously. But he took redemption seriously. And it was incredibly powerful the way he did it.'

In 2005, Graham spoke to CNN about his late wife, Ruth. 'I don't think I could have ever married anybody that would have been more helpful to my work and ministry than she has been,' he told Larry King.

She died in 2007 at the couple's Montreat home. 

Graham himself suffered from cancer, pneumonia and other ailments before dying today.

He is survived by his five children, including his well known son Franklin, and 19 grandchildren.