After nearly ten years in Kanara, he returned to Goa, and in 1686 he founded an Oratory of Saint Philip Neri there with a group of other priests, receiving advice and help from the Oratorian houses then in Portugal. Only one year later, in 1687, he felt called to leave Goa and go as a missionary to the island of Ceylon now Sri Lanka.
He remained on that island for twenty-four years, exercising his priestly ministry in very restrictive circumstances. He was rigorously pursued and persecuted by the oppressive Dutch Calvinist authorities who wanted to put an end to his single-handed yet successful efforts at rebuilding the Church and keeping Catholicism alive in Ceylon. He had to travel everywhere in disguise and was obliged to celebrate the sacraments secretly at night.
Fr. Vaz decided to make his base in the kingdom of Kandy in the island’s interior. On his arrival there he was arrested as a spy and put in prison. He was released after he had prayed for and obtained what was regarded by all as a miraculous fall of rain, ending a prolonged drought. After that the Buddhist king of Kandy gave him his personal protection.
In 1696 several Fathers of the Oratory in Goa joined him in Ceylon and a properly constituted mission was established there. Fr. Vaz refused the position of Vicar Apostolic, preferring to remain a simple missionary priest. Among his other pastoral work he translated a catechism and prayers into the local languages, Singalese and Tamil. The people called him ‘Sammanasu Swam’ – the angelic priest.
By the start of 1711, he knew he was dying. On 16th January he received the Last Rites with members of his flock gathered around his bed. He told them, “Always live according to God’s inspiration. He died at midnight. He was sixty years old.
Unfortunately, the exact whereabouts of his remains is uncertain.
He was beatified in Sri Lanka by Pope John Paul II on 21st June 1995, and was canonized there by Pope Francis on Wednesday 14th January 2015.
His feast day is celebrated on 16th January.