I write in the devout hope that Fr Justin Nary is still alive. He is the remarkably courageous priest in the Central African Republic who was last week reported to have sheltered 800 Muslims inside his church - and defied the self-styled Christian militia outside who wanted him to hand over the innocents to be slaughtered.

Muslims are being driven from large swaths of the country by "anti-balaka" vigilantes, who are taking revenge for similarly barbarous acts by the Seleka, an Islamist militia which rampaged through the country last year, killing and terrorising Christians, and looting their homes, shops, schools, hospitals, and churches (News, 13 December). All this is happening in a country where the two faiths had previously lived peaceably side by side for generations.

The Christian bandits have told Fr Nary that if he does not expel those taking sanctuary in his compound, they will burn down the church with him inside it. Indeed, they have been back once with 40 litres of petrol, and left only when the priest paid them to go. He did not know, he told a BBC reporter, Tim Whewell, what would happen now.

Courage is often portrayed nowadays as an individual act, as with a heroic action on the battlefield. But there seems something even braver about someone whose acquaintance with danger is sustained or repeated.

Next week, a BBC World Service documentary, which can be heard in the UK on digital radio, tells the story of one of the unsung heroes of the genocide in Rwanda, 20 years ago next month. Captain Mbaye Diagne was an officer in the Senegalese Army who was working with the UN's peacekeeping mission in a country in which well over half a million people, mainly ethnic Tutsis, but also moderate Hutus, were killed by blood-crazed Hutu militants.

In the midst of all this - and in defiance of his restrictive UN brief not to intervene to rescue civilians - Captain Diagne saved nearly 600 individuals by smuggling them, in groups ofthree or four, under blankets in his car, past the roadblocks set up around Kigali to manage the ghastly ethnic cleansing.

He did so at great personal risk. He began by rescuing the children of the moderate Hutu Prime Minister, who had just been murdered with his wife and ten Belgian paratrooper bodyguards. But he continued throughout his tour of duty, rescuing anyone whom he came across who was in distress.

His secret weapons were cheeriness and charm. He cracked jokes with the wild men at the roadblocks, or bribed them with money, cigarettes, or whisky, which he, although a Muslim, carried in his vehicle specifically for that purpose.

But courage takes its toll. Only 12 days before he was due to return home, the captain ranghis wife back in Senegal. His talk seemed unusually preoccupied with death, she tells the documentary-maker, the reporter Mark Doyle - who was personally saved from execution by Captain Diagne. Not long afterwards, the Captain died when a mortar struck his vehicle. "He was the bravest of all," a fellow peacekeeper recalls - not least because he showed such bravery at a time when the rest of the world was demonstrating cowardice.

Paul Vallely is Visiting Professor in Public Ethics and Media at the University of Chester.