After Monsignor
Martinho da Costa Lopes was removed as apostolic administrator in 1983, his position remained vacant until Belo was appointed titular bishop of
Lorium and apostolic administrator of the
Diocese of Dili, the senior official of the Catholic Church in East Timor, on 21 March 1988. On 19 June 1988, he was consecrated a bishop by the
Apostolic Nuncio to Indonesia, Archbishop
Francesco Canalini. He chose as his episcopal motto
Caritas Veritatis-Veritas Caritatis. Belo continued on Lopes' path and after five months of taking office he preached a sermon that denounced the
Kraras massacre of 1983 and condemned the many Indonesian arrests. He undertook a program of overseas contacts to counter the world's ignorance of the violence in East Timor. In February 1989 he wrote to the president of Portugal, the pope, and the secretary-general of the United Nations calling for the UN to sponsor and oversee a referendum on the future of East Timor and for international assistance for the East Timorese, who were "dying as a people and a nation". This appeal to the UN became public in April. He further antagonized Indonesian authorities when he gave sanctuary in his own home to youths escaping the
Santa Cruz massacre in 1991 and endeavoured to expose how many were killed. Belo's labours on behalf of the East Timorese and in pursuit of peace and reconciliation were recognised when, along with
José Ramos-Horta, he was awarded the Nobel Peace Prize on 10 December 1996. Belo capitalised upon this honour by meeting with a variety of world leaders, including US President
Bill Clinton and
Nelson Mandela of South Africa. Following East Timor's independence on 20 May 2002, Belo went to Portugal for several months of medical treatment. He later said he was "suffering from both physical and mental fatigue that will require a long period of recuperation". He and Bishop
Basílio do Nascimento, the administrator of another diocese in East Timor, met privately with the pope on 28 October 2002.
Pope John Paul II accepted his resignation as
Apostolic Administrator of Dili on 26 November 2002. Nascimento was named to succeed him. The Vatican announcement did not explain his retirement at the age of 54, but cited the provision of canon law that allows a bishop to retire for grave reasons or health problems. ==Later activity==