尊室說
Before the second French attack of Tonkin in 1882 (part of the Tonkin Campaign), Phạm Thận Duật had issued a secret report to the Huế court, laying out defensive measures against the enemy. He advocated for the construction of forts in critical mountainous areas, and anti-French military bases in Quảng Bình, Hà Tĩnh, with an especially large-scale one in Tân Sở, Quảng Trị. His plan was approved by the leading officials of the pro-confrontation faction of the court, Tôn Thất Thuyết and Nguyễn Văn Tường.