In 1798 the emperor Cảnh Thịnh ordered the destruction of the Catholic churches of Vietnam, and the Catholics of the Quảng Trị region fled into the rainforest at La Vang, where cold, hunger and fever killed many. Gathered at night under a great tree to pray the Rosary, they saw, by their account, a Lady in the old Vietnamese dress holding a child, with angels about her, who comforted them, told them to boil the leaves of the trees around them against their sickness, and promised that all who came to pray in that place would be heard.
A chapel followed the persecution; the church built in 1901 was declared a minor basilica by John XXIII in 1961; and in 1972 it was destroyed in the war. Our Lady of La Vang is the patroness of Vietnamese Catholics, at home and in the diaspora, and the triennial pilgrimage on 15 August draws hundreds of thousands.
No formal judgement has ever been made on the apparition, and the Holy See has said it holds no documentation of it. What the Church has approved is the devotion: John Paul II, canonizing the 117 Vietnamese martyrs on 19 June 1988, spoke of La Vang and asked that the basilica be rebuilt for the bicentenary of the apparition. The site records it on those terms — a tradition honoured, not an event judged.