Roger de, an historian and critic of art, was born of a noble family at Clameci in 1635. His love for painting appeared early, and was never lost amid the public business which engrossed his life. Travelling as tutor, and then as secretary, to the son of President Amelot, he sedulously increased and matured his knowledge of pictures. Sent as a spy of the French king to the Hague, he practised the profession of a painter in order to conceal his real character. Nor could a Dutch prison damp his enthusiasm for art. During his confinement he wrote his principal work, the Lives of the Painters. Piles died at Paris 1709. A collection of the works of this author was published in 5 vols. 12mo, 1767.

PILEUS and PILEUM (πῖλος and πῖλος), were terms applied by the Greeks and Romans to any piece of felt, and particularly to a felt cap, a hat made to fit close to the head, and without any brim. The pileus was usually of a half-egg shape, but was frequently more elevated. The Greeks, who bequeathed the art of felting to the Romans, doubtless derived it themselves from Asia. The Phrygian cap or bonnet, which was of a similar shape and texture to the pileus, seems to have been peculiar to the inhabitants of Asia Minor generally, as we find it continually introduced by artists as the symbol of Asiatic life. The felt cap was the emblem of liberty among the Romans. When a slave obtained his freedom, he exchanged the hair of his head for an undyed pileus.

In contradistinction to the brimless pileus, the Greeks and Romans wore the petasus (πέτασος), a species of hat also made of felt, and consisting of a great variety of forms, from that of a mere circular disk to shapes closely resembling our "wide-awakes."