Roger de Piles (7 October 1635 – 5 April 1709) was a French painter, engraver, art critic and diplomat.
Born in Clamecy, Roger de Piles studied philosophy and theology, and devoted himself to painting.
In 1662 he became tutor to Michel Amelot de Gournay, whom he was to follow throughout his life, acting as secretary to his various missions as French ambassador to Venice, Portugal, Spain.
In Venice (1682–1685) he started a famous collection of prints, drawings and paintings of Giorgione, Correggio, Rembrandt, Claude Lorrain, Rubens, Antoine Coypel, Jean-Baptiste Forest.
He also acquired a taste for political intrigue using his travels ostensibly undertaken to study the European collections, as a buyer for Louis XIV, as cover for confidential missions - for example in Germany and Austria (1685) on behalf of Louis' minister, the marquis de Louvois.
He was not always fortunate as a spy. In 1692, during the War of the League of Augsburg, he was arrested in the Hague carrying a false passport and imprisoned for the next five years. He spent his time writing L'Abrégé de la vie des peintres ...avec un traité du peintre parfait. published in 1699 following his appointement as Conseiller Honoraire to the Académie de peinture et de sculpture.
In 1705 he followed Amelot de Gournay to Spain but illness forced him to return to Paris, where he died in 1709.
His important contribution to aesthetic theory rests on his Dialogue sur le coloris ("Dialogue on colours"), in which he initiated his famous defence of Rubens in the argument started in 1671 by Philippe de Champaigne on the relative merits of drawing and color in the work of Titian (in a lecture to the Académie de peinture et de sculpture on Titian's Virgin and Child with St John.)