He spent time in Bergamo, as is documented by the altarpiece with Madonna and Saints in the parish church of Villa d'Adda, signed and dated 1656. In Bergamo, the artist got to know Count Carlo Giacomo Vecchi, the still-life painter Evaristo Baschenis and art dealer Alberto Vanghetti, for whom he painted numerous paintings and with whom he remained in correspondence until 1657. He then travelled to Venice at the invitation of Nicolò Sagredo, who had been Venice's ambassador to Rome, having already met his brother Guillaume in Rome. Sagredo commissioned Courtois to paint two lunettes above the side doors in the church of St. Mark as well as sacred stories in the gallery.