This historiographic article aiming to contribute to the history of Oriental scholarship in Belgium deals with the birth of the Belgian Society of Oriental Studies (1921-), on the basis of an annotated edition of a letter dated December 1920 by the Indologist Louis de La Vallée Poussin (1869-1938) to the philologist and historian of religions Franz Cumont (1868-1947), in which the former proposes to the latter to become the president of the society of Oriental studies he is about to start. Cumont, who was then living in Roma (where his archives now lay in the Academia Belgica) declined the proposal, and La Vallée Poussin was elected president at the inaugural session of the society on the 9th of January 1921. The history of the young society is traced from this time until the death of La Vallée Poussin in 1938, using the information provided by several reports of the sessions published in the Revue belge de philologie et d’histoire. The paper gives bio-bibliographical data on the various Belgian scholars more or less involved in the activities of the society, and adds a complete list of the works which were published by the society between 1923 and 1935.