What role did music play in Nelson Mandela's life?
A documentary by Canadian filmmaker Jason Bourque explores how the former South African President, who has died at the age of 95, used song as a powerful weapon against apartheid.
Nelson Mandela once said: "Music is a great blessing. It has the power to elevate and liberate us. It sets people free to dream. It can unite us to sing with one voice. Such is the value of music."
Filmed in 2011, Music for Mandela examines how Nelson Mandela used music both personally and politically throughout his life.
"It was made as a tribute to our greatest living icon," Bourque told the BBC earlier this year, as the documentary began screening at film festivals. It won the audience choice award at the Amnesty International Film Festival 2013 in Vancouver.
Bourque and producer Ken Frith spent their teenage years on opposite sides of Canada, but in 1988 both were among the TV audience of 600 million watching the live broadcast of Mandela's 70th Birthday Tribute concert at London's Wembley Stadium.
"It made an indelible mark on me," Bourque said. " I was about 16 and you know how important music is at that age. I was a fan of Peter Gabriel, Simple Minds, Dire Straits, Sting and George Michael - so it was through my favourite artists that I became aware of Nelson Mandela."
Nine years later, Bourque and Frith met at the Vancouver Film School and later formed Gold Star Productions, making documentaries, films, music videos and commercials.
Having had their Mandela project in their minds for many years, production got underway two years ago. Music for Mandela was filmed over six months in South Africa, Canada and the UK and features musical performances from Ladysmith Black Mambazo and the Soweto Gospel Choir.
Interviewees include BB King, Sean Paul, Estelle, classical singer Katherine Jenkins and Mandela's grandson, hip hop artist Bambatha Mandela.
"What was interesting for me," said Bourque, "is that throughout this process I began to see music as more of a weapon."
Nelson Mandela was convicted of treason and sabotage in June 1964 and sentenced to life imprisonment. He spent most of his sentence on Robben Island, off Cape Town, doing hard labour.
While imprisoned, Mandela's influence grew through freedom songs and he became a symbol for the movement to end apartheid.
As Jonas Gwangwa, the former exiled South African jazz musician, says in the film: "His name was kept alive especially through music. When people sang about Mandela... the young generation would ask 'who is Mandela?' Then we would explain."
Mandela himself would use song to lift the spirits of his fellow prisoners.
One of the highlights of the documentary is when Eddie Daniels, an ex-prisoner and long-time friend of Mandela, sings Bonny Mary of Argyle, a song that Mandela used to sing behind bars.
"Mandela and the prisoners would give Christmas concerts - and the music would resonate through the prison walls," Bourque said. "In prison there were subversive folk songs that they could sing and get away with."
Bourque's film also considers the cultural ban on images and music inspired by Mandela. Hundreds of records were banned - including Pink Floyd's The Wall, which had been adopted by protesters against educational inequities under apartheid.
"Songs that had anything to do with Mandela would literally be scratched off the LP by the censor," explained Bourque.
Banned music was smuggled on cassettes, or beamed into the country by shortwave radio transmitters, while exiled musicians travelled the world singing about the plight of the South African people.
Another first-hand account in the film comes from hip hop artist Bambatha Mandela, who was a baby when his grandfather was released in 1990.
"Music in general is part of our South African culture and it's also part of what got us through the struggle," he says in the film.
He also performs his rap-song Born African. Bourque recalled: "We had his grandson telling us these wonderful stories about growing up with Mandela and then he rapped about it. It was a wonderful moment."
The documentary highlights the influential role of The Special AKA's hit protest song Free Nelson Mandela. First released in 1984, it reached number nine in the UK charts.
"It seemed to plant the seed for the entire 70th birthday tribute," Bourque said.
"It was one of the songs they would have had to smuggle into South Africa. People were aware of it, but it was banned. You would have to travel miles to a friends' house and listen to it behind closed doors."
How did that 1988 concert change things?
"When I look back at it - and the power of music and the simple message - without a doubt it raised the global consciousness as to what was going on," he said.
"That was the the way that the majority of the world found out about Mandela's plight and that of the South African people. You can't deny how many people were touched by that concert."
Watch the official trailer for Music for Mandela