At this point in his life, larger historical forces intervened. The Franco-Spanish invasion force landed in nearby Đà Nẵng harbour in August 1858 with the purpose of advancing European commercial and religious interests in Indochina. In a largely ineffective attempt to prevent communication between the invaders and the locally resident Catholic missionaries and their Vietnamese disciples, the Huế court of Emperor Tự Đức reinforced its legislation against Catholic proselytism (known in Vietnamese as dụ cấm đạo or "edict interdicting the religion") by imposing stricter penalties and exhorting the imperial officials to be more strident in enforcing them. To escape Huế's anti-Catholic restriction, Gauthier and Nguyễn Trường Tộ fled to Đà Nẵng in 1859, placing themselves under the military protection of the besieged European forces then occupying central coast enclaves in the vicinity. From Đà Nẵng, Gauthier took Nguyễn Trường Tộ to Hong Kong, Penang in Malaysia, and other places in Southeast Asia where the Foreign Missions Society had established seminaries.