柴门霍夫
The Declaration on the Essence of Esperantism (), commonly referred to as the Declaration of Boulogne ("Bulonja Deklaracio"), is a historic document that establishes several important premises for the Esperanto movement. The Declaration was written by L. L. Zamenhof and ratified in 1905 by the attendees of the first World Esperanto Congress, held in Boulogne-sur-Mer, France.