Dome

[1][a] Across the ancient world, curved-roof structures that would today be called domes had a number of different names reflecting a variety of shapes, traditions, and symbolic associations.

[33] The outward thrusts in the lower portion of a hemispherical masonry dome can be counteracted with the use of chains incorporated around the circumference or with external buttressing, although cracking along the meridians is natural.

[34] Unlike voussoir arches, which require support for each element until the keystone is in place, domes are stable during construction as each level is made a complete and self-supporting ring.

[39] According to E. Baldwin Smith, from the late Stone Age the dome-shaped tomb was used as a reproduction of the ancestral, god-given shelter made permanent as a venerated home of the dead.

[42] The dual sepulchral and heavenly symbolism was adopted by early Christians in both the use of domes in architecture and in the ciborium, a domical canopy like the baldachin used as a ritual covering for relics or the church altar.

[47] Cavities in the form of jars built into the inner surface of a dome may serve to compensate for this interference by diffusing sound in all directions, eliminating echoes while creating a "divine effect in the atmosphere of worship."

The trade-off between the proportionately increased horizontal thrust at their abutments and their decreased weight and quantity of materials may make them more economical, but they are more vulnerable to damage from movement in their supports.

The Himba people of Namibia construct "desert igloos" of wattle and daub for use as temporary shelters at seasonal cattle camps, and as permanent homes by the poor.

[106] Due to the scarcity of wood in many areas of the Iranian plateau and Greater Iran, domes were an important part of vernacular architecture throughout Persian history.

In 1088 Tāj-al-Molk, a rival of Nizam al-Mulk, built another dome at the opposite end of the same mosque with interlacing ribs forming five-pointed stars and pentagons.

They are generally thinner than earlier domes and are decorated with a variety of colored glazed tiles and complex vegetal patterns, and they were influential on those of other Islamic styles, such as the Mughal architecture of India.

[119][120] During the Three Kingdoms period (220–280), the "cross-joint dome" (siyuxuanjinshi) was developed under the Wu and Western Jin dynasties south of the Yangtze River, with arcs building out from the corners of a square room until they met and joined at the center.

[118] The Seokguram Grotto (751), built in the Korean city of Gyeongju during the Unified Silla period, includes a domed chamber 7.2 meters wide covering a statue of the Buddha.

[133] The technique of building lightweight domes with interlocking hollow ceramic tubes further developed in North Africa and Italy in the late third and early fourth centuries.

[141] "Cross-domed units", a more secure structural system created by bracing a dome on all four sides with broad arches, became a standard element on a smaller scale in later Byzantine church architecture.

[149] The Syria and Palestine area has a long tradition of domical architecture, including wooden domes in shapes described as "conoid", or similar to pine cones.

When the Arab Muslim forces conquered the region, they employed local craftsmen for their buildings and, by the end of the 7th century, the dome had begun to become an architectural symbol of Islam.

The more modern and safe method of gold electroplating was applied for the first time in gilding the domes of the Cathedral of Christ the Saviour in Moscow, the tallest Eastern Orthodox church in the world.

[23] Ottoman architecture made exclusive use of the semi-spherical dome for vaulting over even very small spaces, influenced by the earlier traditions of both Byzantine Anatolia and Central Asia.

[185] At the time it was built, the dome was the highest in the Ottoman Empire when measured from sea level, but lower from the floor of the building and smaller in diameter than that of the nearby Hagia Sophia.

[188] A combination of dome, drum, pendentives, and barrel vaults developed as the characteristic structural forms of large Renaissance churches following a period of innovation in the later fifteenth century.

[192] De re aedificatoria, written by Leon Battista Alberti around 1452, recommends vaults with coffering for churches, as in the Pantheon, and the first design for a dome at St. Peter's Basilica in Rome is usually attributed to him, although the recorded architect is Bernardo Rossellino.

Palladio's two domed churches in Venice are San Giorgio Maggiore (1565–1610) and Il Redentore (1577–92), the latter built in thanksgiving for the end of a bad outbreak of plague in the city.

[197] Hemispherical rock-cut tombs appear to imitate in stone the early bamboo or timber roofed domed huts with central poles known from the pre-Buddhist period.

[198] The hemispherical shape of Buddist stupas, likely refined forms of burial mounds, may also reflect earlier wooden dome roof construction, such as at Ghantasala.

[200] Domes in pre-Mughal India have a standard squat circular shape with a lotus design and bulbous finial at the top, derived from Hindu architecture.

However, many bulbous domes in eastern Europe were replaced over time in the larger cities during the second half of the eighteenth century in favor of hemispherical or stilted cupolas in the French or Italian styles.

[210] The construction of domes in the sixteenth and seventeenth centuries relied primarily on empirical techniques and oral traditions rather than the architectural treatises of the times, which avoided practical details.

[81] Robert Hooke, who first articulated that a catenary arch was comparable to an inverted hanging chain, may have advised Wren on how to achieve the crossing dome of St. Paul's Cathedral.

[191] In the late 19th and early 20th centuries, the Guastavino family, a father and son team who worked on the eastern seaboard of the United States, further developed the masonry dome, using tiles set flat against the surface of the curve and fast-setting Portland cement, which allowed mild steel bar to be used to counteract tension forces.