Pierre Joseph Georges Pigneau (2 November 1741 in Origny-en-Thiérache – 9 October 1799, in Qui Nhon), commonly known as Pigneau de Béhaine (French: [pi?o d? be.?n]), also Pierre Pigneaux, Bá Ða L?c ("Pedro" ???), Bách Ða L?c (???) and Bi Nhu ("Pigneau" ??), was a French Catholic priest best known for his role in assisting Nguy?n Ánh (later Emperor Gia Long) to establish the Nguy?n dynasty in Vietnam after the Tây Son rebellion.