Father Mussie Zerai was a theology student in Rome when he first got a call from a boat in the middle of the Mediterranean Sea.
He thought it was a joke: "It was three o'clock in the night. I think, who is calling me? Even the number is different because it is a satellite phone. He is speaking my language and I think, maybe it is one of my friends.
"Then when I start to hear people who are shouting, they are saying ‘help us, we are in danger,’ I say ‘what is this?’. Then when someone starts to say his name, I understand something is wrong. I say OK, but what can I do now?"
That was back in May 2003.
"I did not know what to do," he recalls, "It was the first time. I did not have any experience."
So Eritrean-born Zerai ran to the room of his rector, banged on the door, and told him: "I have this case, I don't know who is in charge of this kind of thing."
"And he told me 'you need to call the coast guard'. So I found the number, and I did."
What started as a one-off call in the middle of the night soon snowballed into a mountain of distress calls from refugees fleeing their home countries to find refuge in Europe.
"At the beginning, it is panic," Zerai says of the telephone calls. "You need to give time to calm them. It is hard. It is really stressful. First you don’t sleep because much of the time, this call arrives at the middle of the night, two o’clock, three o’clock, the middle of the night. So you wake up and you concentrate. And you spend a lot of energy, first to make them trust you because it is necessary to give them hope. For them it is important to realise you are there to help them. So I give them a few minutes at the beginning and I say I am here for you, I am here to help you, so be calm, be patient, give me all the information I need. Without that I can’t help you.
"And when the people stop shouting and become calm, then I start asking them questions."
It wasn't until 2011, when a New York journalist was reporting on the aftermath of the Libyan revolution, that Zerai found out why he had been chosen as the refugees' saviour. The priest's mobile phone number had been painted on the wall of a detention centre in Libya. "So all the people who passed by that detention centre had my phone number," Zerai explains.
So how did the mobile number of an Eritrean priest training in Rome end up on the wall of a detention centre in Libya?
Zerai started his humanitarian work in 1995, when he decided to dedicate more time to assisting migrants and foreign workers, primarily from Eritrea and Ethiopia, and then increasingly from East Africa, to help them bridge the gap between civil organisations, charities and institutions.
"The basic thing is to create a network for facilitating these people's lives. To guarantee them the basic things - documents, shelter, a job. Even helping them deal with the bureaucracy. So this is how I start."
Zerai's first contact with refugees was in 2003, as a translator. He was contacted by an Italian journalist who travelled to Libya in 2003. "He was in contact with Ethiopian and Eritrean refugees in a detention centre in Misrata. He asked me to translate for him the story of these people. Then he gives my number to them. To stay in touch with me to explain to me what is going on every day."
After an agreement between Libya and Italy in 2004, which saw the two countries team up to tackle the mass migration from North Africa to Italy, Zerai started to monitor the conditions of the detention centres, which were funded by the European Union, to ensure the human rights of the detainees were being respected.
"I started to collect all the stories," he remembers. "And I hear all the stories of these people, the bad treatment, torture, rape, a lot of sexual abuse, especially for women - and even for men. I realise I can’t limit myself only to translate for this journalist, who wants to write a book. I need to denounce [the issues] publicly." He raps on the table to reinforce his point. "Because it is necessary to create awareness of this situation, and the responsibility of the EU, because the EU is funding this detention centre."
Every day the Italian journalist phoned Zerai to feed him more information, until finally, with the help of Unicef and other charitable organisations, the refugees were released from the centre. A few months later, Zerai received his first distress call.
But his work did not end there. When the UN-backed bombing of Libya began in 2011, 40-year-old Zerai coordinated with the European Union to evacuate those held in other detention centres in Libya to the Choucha camp in southern Tunisia. However he realised he couldn't communicate with each and every refugee by telephone.
"So I say OK, I can use the radio," he tells me. "So I use the Voice of America in the US, Radio Erena in France, Deutsche Welle in Germany. I use these channels to give a message for my people in Libya, to give them the coordinates to go to the camp, and from there we can organise the resettlement programme.
"One radio journalist who had my number broadcast it [over the airwaves]. So at that time, all the people, in Libya, Sudan, Egypt, in Eritrea, Ethiopia, had my number. It become a really public phone number from that time."
From 2011 onwards, Zerai's phone became very busy. "Each second it was ringing." The priest, who was recently nominated for the Nobel Peace Prize, estimates he has helped thousands of refugees, particularly in the last decade. He no longer works as a one-man band, but has his own team of volunteers who help him - the Habeshia Agency, which he founded in 2006.
"We also have another network, not founded by me, but I encouraged them and give them advice," he explains. "After 2011, a group of volunteers come to ask me if they can help me in some way. I say yes, we can create a network with a call centre, and now we have this centre, it’s called Watch The Med.
"Because it is important to have people who can speak different languages. The people from the Mediterranean Sea, sometimes they speak my language, some other times only English, French, Arabic, or Kurdish, so now I have this network.
"When I receive any distress call, if I am able to communicate with them I do myself. If that person doesn’t speak my language then I pass this call to the call centre. I say ‘I have this case, he speaks this language, find someone who can help us to help all the information I need.’ And they do."
I wonder aloud how faith can help someone who has seen so much suffering and is burdened with the responsibility of saving so many lives.
Zerai doesn't miss a beat. "Without faith, I cannot survive," he replies. "Because every day you hear a lot of problems, stories, tragedies. For me my faith and my prayer time are important to eradicate all this pain.
"I've had a lot of support from the Church. It’s an important role for them to help vulnerable people. This is the biggest crisis. It is the biggest crisis of our time. We have more than 60million refugees around the world. It’s not happened before.
"Most of the time the politicians, even mass media, are talking about numbers. But, this is not only a number. This is a person, a human being, a story, a dream, a hope. It is important that we put the human being, the human dignity at the centre of what we talk about.
"These people, they come, they escape from their home country to find freedom, justice, life. These people are not only desperate, they have a hope to build a real, new life. These people explain to us how important freedom is. How important justice is. Social justice, economical justice, basic justice. How important the life is."
Giving aid to these people in some of the most desperate times of their lives is Zerai's way of building peace, he explains. "When I help some of them, I say, today I give my contribution; for peace, for justice, for democracy, for freedom. Each one person I can help is the base to construct peace. This man, this woman, this children - they can start a new life in this new country. That is the base.
"And I realise, if someone asks me what is the base of the human rights, I say love your brother and your sister like yourself." He bangs each syllable out on the table. "So, when I help someone, I realise this." Here he points directly at me, and fixes his gaze so I'm forced to stop taking notes. "I love you. So I give you the same chance that I have. I give you the same opportunity. The same conditions where I am and where I live. That means I create a space for you. I create a space near me, near my home and my life.
"When I start to fight for your right, I am fighting not only for you, but for myself. Because today you" - he points again - "you are in danger. But maybe tomorrow I am in your condition.
"When I defend you, when I stand for you, I am standing for myself too. For my dignity. For everyone's dignity. Because everyone deserves to live with dignity."
Father Mussie Zerai is an ambassador for One Young World, a global forum for young leaders aged 18-30 which gathers youths from every nation in the world to develop solutions to some of today and tomorrow's most pressing issues.