dome, a roof circular or (rarely) elliptical in plan and usually hemispherical in form, placed over a circular, square, oblong, or polygonal space. Domes have been built with a wide variety of outlines and of various materials.

Early Domes

The earliest domes were probably roofed primitive huts and consisted of bent-over branches plastered with mud. Another primitive form, called a beehive dome, is constructed of concentric rings of corbeled stones and has a conical shape. Ancient examples have been found in the tombs of Mycenae and can also still be seen in the folk architecture of Sicily. Although there is evidence of widespread knowledge of the dome, its early use was apparently restricted to small structures built of mud brick.

Roman and Byzantine Domes

It was the Romans who first fully realized the architectural potentialities of the dome. The Roman development in dome construction culminated in the pantheon Pantheon at Rome was built by Agrippa in 27 B.C., destroyed, and rebuilt in the 2d cent. by Hadrian. Remarkably well preserved, it is mainly of brick with a great hemispherical dome whose supporting walls are set in concrete.
..... Click the link for more information. (2d cent. A.D.). The Romans, however, failed to discover a proper handling of the pendentive pendentive, in architecture, a constructive device permitting the placing of a circular dome over a square room or an elliptical dome over a rectangular room.
..... Click the link for more information. —the device essential to placing a dome over a square compartment—that was finally achieved by the Byzantine builders of Hagia Sophia Hagia Sophia (hä`jə sōfē`ə, hā`jēə,) [Gr.
..... Click the link for more information. at Constantinople (A.D. 532–37). The other solution to placing a dome over a square was the squinch squinch, in architecture, a piece of construction used for filling in the upper angles of a square room so as to form a proper base to receive an octagonal or spherical dome.
..... Click the link for more information. , which in the form of stalactites was to receive superb expression in Islamic architecture. Under Byzantine influence the Muslims early adopted the use of the dome; one of their first important monuments is the Dome of the Rock in Jerusalem. They often used the so-called Persian or onion dome. The most celebrated example is the Taj Mahal Taj Mahal (täzh məhäl`, täj məhŭl`), mausoleum, Agra, Uttar Pradesh state, N India, on the Yamuna River.
..... Click the link for more information. (A.D. 1630) at Agra, India.

Renaissance Refinements

Both the influence of the Roman Pantheon and of the Byzantine pendentive came to bear on the designers of the Italian Renaissance, and the crossings of many churches of the period were covered by masonry domes on pendentives. Between pendentive and dome a circular drum usually was interposed, serving to give greater elevation and external importance as well as a space for the introduction of windows. By the addition of an outer shell, the exterior came to be independently designed for maximum effectiveness, and the placing of a lantern at the top of this outer shell provided an apex for the entire composition.

Modern Domes

The dome in modern architecture utilizes such materials of construction as reinforced and thin-shell concrete, glass and steel, and plastic. An innovative contemporary approach to the form is the geodesic dome geodesic dome (jē'ədĕs`ĭk, –dē`sĭk), structure that roughly approximates a hemisphere.
..... Click the link for more information. . These are low-cost, geometrically determined hemispherical forms as promoted by architect Buckminster Fuller Fuller, R. Buckminster (Richard Buckminster Fuller), 1895–1983, American architect and engineer, b. Milton, Mass. Fuller devoted his life to the invention of revolutionary technological designs aimed at solving problems of modern living.
..... Click the link for more information. .

Outstanding Domes

Celebrated examples are Brunelleschi's octagonal ribbed dome for the Cathedral of Florence (1420–36); St. Peter's, Rome, designed by Michelangelo, with two masonry shells (completed 1590), internal diameter 137 ft (42 m); the church of the Invalides, Paris, by J. H. Mansart (1706), 90 ft (27 m); St. Paul's Cathedral, London, by Sir Christopher Wren (1675–1710), 112 ft (34 m); and the Panthéon, Paris, by J. G. Soufflot (1775–81), 69 ft (21 m). The last three domes are built with triple shells, the middle shells serving to support the crowning lanterns.

In the United States the dome of the Massachusetts state capitol, designed (1795) by Charles Bulfinch, established the dome as a distinctive feature for numerous later state capitols as well as for the national Capitol at Washington, D. C. The dome of the latter, however, is of cast iron instead of masonry. The design, by T. U. Walter, has an inner diameter of 90 ft (27 m) and possesses great external impressiveness.

Bibliography

See E. B. Smith, The Dome: A Study in the History of Ideas (1975).

dome

A dome is traditionally supported primarily by a cylindrical or polygonal drum; it may be …

In architecture, a hemispherical structure evolved from the arch, forming a ceiling or roof. Domes first appeared on round huts and tombs in the ancient Middle East, India, and the Mediterranean in forms, such as solid mounds, adaptable only to the smallest buildings. The Romans introduced the large-scale masonry hemisphere. A dome exerts thrust all around its perimeter, and the earliest monumental examples (see Pantheon) required heavy supporting walls. Byzantine architects invented a technique for raising domes on piers, making the transition from a cubic base to the hemisphere by four pendentives. Bulbous or pointed domes were widely used in Islamic architecture. The design spread to Russia, where it gained great popularity in the form of the onion dome, a pointed, domelike roof structure. The modern geodesic dome, developed by R. Buckminster Fuller, is fabricated of lightweight triangular framing that distributes stresses within the structure itself.