Henri-Joseph Sondag (1835-1893), headmaster of the primary school for boys, decided in 1860 to start a school of vocal music: the Philharmonic Society of Saint-Mard. Its members gathered at the primary school for boys until 1897, when the Ministry of Education had the society expelled.
Mrs Laurent, a Saint-Mard publican (the café was located on the former “Place du Duc de Brabant”, today’s “Place Jean-Philippe Lavallé”), proposed that they use a room of her café.
They accepted the offer and used that room until 1905 when they were granted the right to come back to the primary school for boys. In 1928, the society occupied the covered playground of the school. In 1979, the former primary school built in 1911 was finally put at the disposal of the society.