 After Nguyễn Ánh established the Nguyễn dynasty in 1802, he tolerated Catholicism and employed some Europeans in his court as advisors.His successors were more conservative Confucians and resisted Westernization.The next Nguyễn emperors, Minh Mạng, Thiệu Trị, and Tự Đức brutally suppressed Catholicism and pursued a 'closed door' policy, perceiving the Westerners as a threat, following events such as the Lê Văn Khôi revolt when a French missionary, Fr.