interior decoration adornment of the interior of a building, public or domestic, comprising interior architecture, finishing, and furnishings. Asian and classical cultures used the decorative arts to create elaborate interiors, and they originated forms extensively copied in later times. In Europe during the early medieval period few notable interiors were created except in Islamic Spain and in the Byzantine Empire. Simple movable and hanging objects were the chief furnishings of castles. In the late Middle Ages artistic resources were dedicated to the embellishment of churches and public buildings.

With more settled conditions, Renaissance Italy, influenced by Greek and Roman styles, developed interiors of grandeur and magnificence; popes and nobles employed leading artists to decorate their palaces and villas. Italian forms spread to other countries. Spanish interiors displayed rich color, ornate furniture, decorated leather, and fine textiles. France was an early leader in setting styles, which changed with the sovereigns. Especially influential were the Louis period styles , régence style , Directoire style , and Empire style . England developed notably the Elizabethan style , the Jacobean style , and the Georgian style; some 18th-century styles are known by the names of furniture designers such as Chippendale , Sheraton , and Hepplewhite . Robert Adam correlated interior and exterior architecture, furniture, and accessories.

In America settlers used simple homemade furniture of native woods, homespun fabrics, and pewter. The style, known as Early Colonial, has been revived for re-creating early American interiors. The formal Late Colonial period used modified Georgian mansions and polished mahogany furniture of English type. Pennsylvania German decoration based on European provincial styles is also much reproduced.

The 19th cent. was marked by a departure from old standards of craftsmanship; machine-made furnishings supplied the requirements of the growing middle classes. In the second half of the century William Morris and the Pre-Raphaelites instituted an arts and crafts movement that spread abroad and stimulated a reaction against ornate Victorian decoration. It resulted in a revival of earlier period styles, the simultaneous development of native provincial styles, and an attempt to create a new modern style.

Contemporary styles are international in character. Designers and manufacturers are cooperating to produce low-cost furnishings scaled for small rooms, combining ease of upkeep and functionalism. Units permitting maximum use of wall space are designed on a modular system to allow flexible combinations. Synthetic materials are employed, and materials such as metals and glass are put to new uses. Lighting is emphasized, and arrangement is based on a correlation of scale, balance, comfort, pattern, and color. encyclopedia.