decorative (decorative art) treatment of frames for mirrors and pictures. Before the 15th century in Europe, frames rarely existed separately from their architectural setting and, with the altarpieces or the predellas (base of the altarpiece) they surrounded, formed an integral part of the decorative scheme of the church interior. Such frames were frequently burnished with gold leaf. During the 15th century, when paintings were more generally used as secular wall decorations and domestic furnishings, frames began to be designed independently of their surroundings.

A type of Italian picture frame with exuberant wood carving evolved during the Baroque period, remained fashionable for a long time, and has never been completely abandoned. Carved wood frames with a “swept” outline, introduced in the 17th century, remained popular in France throughout the reign of Louis XV. During the 1740s, English mirror frames in the heavy Palladian architectural style began to give way to more delicate designs that were much influenced by French Rococo examples.

During the Neoclassical period in the last third of the 18th century, both on the European continent and in England, there was a return to simpler outlines and a greater austerity in frame ornament. Composition and plaster frames became popular. After the first two decades of the 19th century, frame design for both mirrors and pictures became increasingly eclectic, many being based on styles of the previous century.

In the 20th century the trend was toward an ever-increasing simplicity, to complement contemporary paintings, mirrors, and architecture. The use of plain, minimal-width frames, as well as materials such as metals and moulded plastic, typified this movement. Ornamental molded frames reviving historic styles, however, retained their popularity into the 21st century for use with older paintings.