18th century classicists used the term to describe a style of art in the 17th century; it meaning: oddly shaped, illogical, absurd, or bizarre. "Baroque" originally referred to an irregularly shaped species of pearl. The expression first characterized the architectural style created in Rome in the 17th century which spread to other countries. This stylized trend, depending on locale, spanned the end of the 16th century to the middle of the 18th, from late mannerism to the Rococo or "rocaille" of the 18th century; and embraced sculpture, painting, architecture and music. This new Roman architectural style finds in painting a visual surprise of illusion and wonder, where the fantastic and imaginary become probable.
Closely linked to the Counter-Reformation, defending and reasserting images; new iconographic themes of martyrdom, vision and ecstasy develop along with the use of allegory.
The Swiss esthetician Heinrich Wolfflin in his Fundamental principles in the history of art (1915) first defined the Baroque mode of vision in the 17th century, opposing it to 16th century Renaissance Classicism with five pairs of concepts:
Classical art is "linear", clearly defining the object by isolating it; Baroque art is "pictorial" in that it privileges visual appearance.
Classicism builds on planes, Baroque art in depth.
Classicism is the art of closed forms, perfectly outlined; Baroque is that of open forms, not contained within an outline.
Classical style is unity formed of multiple parts; Baroque involves an indivisible unity.
Classicism is characterized by the absolute clarity of its subjects; Baroque by their relative clarity
The relief value of Classicism verses the pictorial quality of the Baroque.
"Development of French painting in the 17th century largely eludes these oppositions." Possessing certain affinites with the Baroque esthetic, it also displays classical tendencies strictly its own, which is also seen in French architecture.
1) The Louvre, Paris, 2003.