We use the word 'martyr' to describe people killed for their faith.

It actually comes from the Greek word meaning 'witness'. So it has extra meaning when Jesus tells his disciples in Acts 1.8: 'You will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth.'

In the early years of Christianity when it was considered a dangerous sect, thousands were killed for their faith often by stoning, crucifixion or being executed as a means of entertainment for Romans.

Typically we think of martyrs only existing in the first centuries of Christianity. But in reality people are martyred for their faith across the world today.

Here are five from across the years you should know about:

Stephen:

Stephen is described in Acts 6-7 as a man 'full of faith and of the Holy Spirit'.

He was arrested by the Jewish authorities on charges of blasphemy and the text includes a lengthy defence he gave to the Sanhedrin.

Saul, later to become Paul the apostle, watched on as the Jews dragged Stephen out the city and stoned him to death, making him the earliest martyr in the Church.

Echoing Jesus' words, he said as they were killing him: 'Lord, do not hold this sin against them.'

Simon Peter:

The disciple who once denied he even knew Jesus ended up being killed because he refused to denounce him again.

Peter, the Rock, was executed under the Roman emperor Nero's reign. Tradition holds that he was crucified upside down because he said he was unworthy to die in the same way as his Lord.

Polycarp:

A legend of the early church, Polycarp was Bishop of Smyrna (modern day Izmir, Turkey) after being converted by the disciple John in AD80.

Perhaps best known for his dying moments, he was told he must recant his faith and burn incense to Ceasar but refused.

'Eighty and six years I have served him, and He has done me no wrong', he said. 'How then can I blaspheme my King and Saviour? You threaten me with a fire that burns for a season, and after a little while is quenched; but you are ignorant of the fire of everlasting punishment that is prepared for the wicked.'

Tradition has it that when soldier tried to bind him to the stake he said: 'Leave me as I am. For he who grants me to endure the fire will enable me also to remain on the pyre unmoved, without the security you desire from nails.'

He prayed aloud and was consumed by the fire. A witness of the moment said his death was 'not as burning flesh but as bread baking or as gold and silver refined in a furnace'.

Dietrich Bonhoeffer:

Bonheoffer was a theologian and pastor in Nazi Germany who strongly resisted Hitler's regime.

He was a pacifist who famously wrestled with how to resist the Gestapo's treatment of Jews. In the end he decided it was more sinful to do nothing than it was to kill Hitler so he joined a plot to assassinate him.

The plot failed and he was arrested, tried and eventually executed on 9 April 1945, one month before Germany surrendered.

Jim Elliot and four friends

Jim Elliot was killed on 8 January 1956 along with four missionary friends as they tried to evangelise the Waodani people in Ecuador.

They made contact with some tribe members, thinking they were being accepted. But the tribe was suspicious and began to fear they were being deceived. They decided they should kill the visitors before they were themselves killed.

Ten men arrived at the beach, speared the five missionaries and left the bodies in the water.

However their remarkable story continues as Elliot's widoe Elisabeth went back to the same tribe and successfully worked with them and told them the gospel.