In 1948-1949, the Bélanger family of Saint-Sylvestre found fame in performing "healing miracles."

The children allegedly acquired healing powers after they had seen their deceased sisters dressed like angels and escorted by the Holy Virgin.

Visitors would leave money to the children for their curing deeds, and they received the support of Reverend Emile Bourassa, from neighbouring Saint-Patrice-de-Beaurivage.

The priest of Saint-Sylvestre, Reverend Edmond Pelletier, preached against the "miracles," and in 1949, Archbishop Maurice Roy, in the name of the Archdiocese of Quebec, ruled the affair as a hoax.

[4] From 1953 to 1964, Saint-Sylvestre hosted a Pinetree Line radar station on Mont Saint-Marguerite, just five miles southeast of the village.