Introduced into Spain by the Arabs during the Moorish occupation.
Azulejos were used in Islamic architecture for facing walls and paving floors.
Early designs were geometric and 5–6 in. (13–15 cm) square.
In the 15th–16th centuries Portugal imported the tiles from Spain for use in religious and private buildings.
The Portuguese exported them in the 17th century to the Azores, Madeira, and Brazil, and the Spaniards introduced them to their American colonies.
In the 18th century, interiors and exteriors in Puebla, Mex., were covered with azulejos in brilliant colours on a scale unequaled elsewhere.
Tiles are usually formed by pressing moist clay into a mold; modern floor tiles are often machine pressed from fine-grained clay.
Tiles can also be slip cast, or formed by pouring slip (liquid clay) into a porous mold and allowing it to stiffen.
Glaze and metal oxide–painted designs may be added before the tile is fired.
Depending on the clay and the firing temperature, fired tiles range from porous earthenware to hard, highly vitrified porcelain.
Tile roofs of clay and (for temples) marble were used in ancient Greece; in Rome, tiles of clay and of gilded bronze were used for roofs.
In medieval northern Europe, clay tile roofs were superseded by roofs of lead, zinc, and stone, but in southern Europe red and orange clay roof tiles continued in wide use.
Modern architects sometimes employ large cast-cement roof tiles. In medieval China, brilliantly glazed roof tiles (often yellow) with heavy relief ornament were used for temples.
Unglazed roof tiles were often black (those in Japan, gray), suggesting a different firing method from that used for European tiles.
The three common systems for tile roofs are an underlayer of concave tiles covered at the joints by an overlayer of convex tiles; overlapping S-shaped tiles; and flat, shinglelike tiles (sometimes of stone).
Unglazed tiles have also been used for wall decoration since ancient times. Modern architects can choose from a wide range of glazed and unglazed, smooth and textured wall tiles, and they often commission handmade tile murals from artist-potters.
For further information on this topic, see the Bibliography, sections Building construction, Floor coverings.
Although mosaic tile floors were known in ancient times, tile floors became common only in the late Middle Ages. French churches of the 12th century had mosaic floors in black, green, and yellow tiles.
The floors of 13th-century cathedrals were often of encaustic tile (reddish clay tiles inlaid with patterns in white and yellow clay). In the 16th century encaustic tile was displaced by Italian and Spanish majolica floor tiles (see POTTERY).
Tile floors gave way to wood and marble floors in the 17th century, but in the 18th century, quarry tiles (plain red tiles) came into widespread use.
The most common modern ceramic floor tiles are small, highly vitrified, machine-pressed tiles in various colors.
The most spectacular ancient tile and tilelike walls were the brilliantly colored glazed-brick and glazed-tile murals of Mesopotamia, Assyria, and Babylonia.
Deep relief decoration characterized the glazed wall tiles of China. Medieval Iran became a center for Islamic tiles, glazed and painted in floral and calligraphic designs.
Spain became famous for its lusterware and majolica tiles. In 14th-century Germany, large heating stoves were made of green-, brown-, and yellow-glazed tiles; these were displaced after about 1600 by stoves of blue-and-white delftware tile.
First made in the Netherlands, delft tiles were admired for their vigorous painting in cobalt blue and, later, manganese purple.