He was born in Guéret and made a troubled way as a man of letters in Paris. He worked as a historian for Gaston, Duke of Orléans. Then through an introductions from Pierre Dupuy he was able to have library access, leading to work on manuscripts for Jean-Baptiste Colbert. Colbert, however, was dissatisfied with his work and replaced him. Varillas enjoyed support from Pierre Huet but became a marginal figure.
His writings attracted a great deal of interest amongst his contemporaries; serious if partisan criticisms of the historical method of his earlier work led to his losing his reputation as a scholar. They included:
Histoire de l'heresie de Viclef, Iean Hus, et Jerome de Prague: avec celle des guerres de Bohéme qui en ont esté les suites;