Balthasar de Monconys (1611–1665) was a French traveller, diplomat, physicist and magistrate, who left a diary, which was published by his son as Journal des voyages de Monsieur de Monconys, Conseiller du Roy en ses Conseils d’Estat & Privé, & Lieutenant Criminel au Siège Presidial de Lyon, 2 vols., Lyon, 1665-1666.
Monconys, brought up in Lyon by the Jesuits and a good Catholic, had an interest in the Jesuit missions in infidel territory. He travelled to Portugal, England, Germany, Italy, the Netherlands and the Near East (visiting Baalbek in 1647). Monconys paid twice a visit to Delft and so could satisfy his curiosity about another hidden church and meet an artist with a growing reputation.[1] He was the only person, besides Pieter Teding van Berckhout, who met with Vermeer on August 11, 1663, and wrote down an eyewitness account of Vermeer's paintings, during Vermeer's lifetime.[2] Vermeer had no paintings to show and Monconys and his companion, a clergyman from The Hague were steered to the baker Hendrick van Buyten. Monconys also visited Johannes Sibertus Kuffler in the same year.