Onion dome
An onion dome, also known as onion cupola, is a dome whose shape resembles an onion. Such domes are often larger in diameter than the tholobate upon which they sit, and their height usually exceeds their width. They taper smoothly upwards to a point.
This feature is typically associated with churches belonging to the Russian Orthodox Church, although they also persist in other Eastern European countries, and occasionally in Western Europe: Bavaria, Austria, and northeastern Italy. Buildings with onion domes are also found in the Oriental regions of Central and South Asia, and the Middle East.
Other types of Eastern Orthodox cupolas include helmet domes, Ukrainian pear domes, and Baroque bud domes or an onion-helmet mixture like the St Sophia Cathedral in Novgorod.
History
According to historian Wolfgang Born, the onion dome has its origin in Syria, where some Umayyad Caliphate-era mosaics depict early stages of the development of bulbous domes. An early prototype of onion dome also appeared in Chehel Dokhter, a mid-11th century Seljuk architecture in Damghan region of Iran.It is not completely clear when and why the onion dome gained popularity in Russian architecture, but buildings featuring them appeared as early as the 13th century, reaching a peak by the 17th and 18th centuries, up until the Petrine period. Some suggest they had a decorative advantage over typical Byzantine and helmet dome, while also not gathering as much snow during severe winters. The largest onion domes of that time were erected in areas around Yaroslavl. A number of these had more complicated bud-shaped domes, whose form derived from Baroque models of the late seventeenth century. Pear-shaped domes are usually associated with Ukrainian Baroque, while cone-shaped domes are typical for Orthodox churches of Transcaucasia.
Later, the Moors also brought the design to Spain, and Islamic influence in the 17th century may be responsible for its introduction in Vienna, where it can be seen on many Baroque structures. Throughout Austria and Bavaria, onion domes top innumerable small churches.
File:1909 Церковь Спасителя и Покрова Пресвятой Богородицы. Вытегорский Погост.jpg|thumb|Wooden churches in Kizhi and Vytegra have as many as twenty-five onion domes
Some scholars suggest that onion domes first appeared in Russia during the reign of Ivan the Terrible. The domes of Saint Basil's Cathedral have not been altered since the reign of Ivan's son Fyodor I, indicating the presence of onion domes in sixteenth-century Russia. Thus, Russians may have adopted onion domes from Muslim countries, possibly from the Khanate of Kazan, whose conquest in 1552 Ivan the Terrible commemorated by erecting St. Basil's Cathedral. Some scholars believe that onion domes first appeared in Russian wooden architecture above tent-like churches. According to this theory, they were strictly utilitarian.
In 1946 Boris Rybakov analysed russian chronicles and concluded, that most of them, from the 13th century onward, feature onion instead of helmet shaped dome, suggesting that this style could not be imported from the Orient, where they did not replace spherical domes until the 15th century Historians like Nikolay Voronin seconded his point of view.
Later Sergey Zagraevsky surveyed icons and miniatures, dating as early as 11th century. He concluded that most icons painted after the Mongol invasion of Rus display only onion domes. The first onion domes were displayed on some pictures of the 12th century. According to him, single icon from the 15th century represented a helmet dome church. His findings led him to dismiss fragments of these dome types discovered by restorators beneath modern onion domes as post-Petrine stylisations intended to reproduce the familiar forms of Byzantine cupolas, like the rebuilt Assumption Cathedral and the Cathedral of Saint Demetrius in Vladimir. As well as restoration works on several other ancient churches that have revealed fragments of former helmet-like domes.
He also indicated that the oldest depictions of the two Vladimir cathedrals represent them as having onion domes, prior to their replacement by classicizing helmet domes. He explains the ubiquitous appearance of onion domes in the late thirteenth century by the general emphasis on verticality characteristic of Russian church architecture from the late twelfth to early fifteenth centuries.
At that time, porches, pilasters, vaults and drums were arranged to create a vertical thrust, to make the church seem taller than it was.
File:Церковь Воскресения Христова на Дебре в Костроме.jpg|thumb|left|Onion domes at the Church of the Resurrection, Kostroma |222x222px
Another consideration proposed by Zagraevsky links the onion-shaped form of Russian domes with the weight of traditional Russian crosses, which are much larger and more elaborate than those used in Byzantium and Kievan Rus. Such ponderous crosses would have been easily toppled, if they had not been fixed to sizeable stones traditionally placed inside the elongated domes of Russian churches. It is impossible to place such a stone inside the flat dome of the Byzantine type, which were characterized by broader, flatter domes without a special framework erected above the drum. In contrast to this ancient form, each drum of a Russian church is surmounted by a special structure of metal or timber, which is lined with sheet iron or tiles, while the onion architecture is mostly very curved. Russian architecture used the dome shape not only for churches but also for other buildings.
Symbolism
Prior to the eighteenth century, the Russian Orthodox Church did not assign any particular symbolism to the exterior shape of a church. Nevertheless, onion domes are popularly believed to symbolise burning candles. In 1917, religious philosopher Prince Evgenii Troubetzkoy argued that the onion shape of Russian church domes may not be explained rationally. According to Trubetskoy, drums crowned by tapering domes were deliberately scored to resemble candles, thus manifesting a certain aesthetic and religious attitude.File:Chukhloma AvraamievMonastery 0564.jpg|thumb|Avraamiev Monastery in Kostroma Oblast, founded in the 14th century
Another explanation has it that the onion dome was originally regarded as a form reminiscent of the aedicula in the Church of the Holy Sepulchre in Jerusalem. The present structure dates back to 12th-century construction by the Crusaders.