An oculus (; ) is a circular opening in the center of a

dome A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a ...

or in a wall. Originating in

antiquity Antiquity or Antiquities may refer to: Historical objects or periods Artifacts *Antiquities, objects or artifacts surviving from ancient cultures Eras Any period before the European Middle Ages (5th to 15th centuries) but still within the histo ...

, it is a feature of

Byzantine The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantin ...

and

Neoclassical architecture Neoclassical architecture is an architectural style produced by the Neoclassical movement that began in the mid-18th century in Italy and France. It became one of the most prominent architectural styles in the Western world. The prevailing sty ...

. It is also known as an ''

œil-de-boeuf An ''oeil-de-boeuf'' (; en, "bull's eye"), also ''œil de bœuf'' and sometimes anglicized as ''ox-eye window'', is a relatively small elliptical or circular window, typically for an upper storey, and sometimes set in a roof slope as a d ...

'' from the

French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...

, or simply a "bull's-eye".

History

Classical

The oculus was used by the

Ancient Romans In modern historiography, ancient Rome refers to Roman civilisation from the founding of the city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–509 B ...

, one of the finest examples being that in the dome of the Pantheon. Open to the weather, it allows rain and air to enter and fall to the floor, where it is carried away through drains. Though the opening looks small, it actually has a diameter of , allowing it to light the building.

Byzantine

The oculus was widely used in the architecture of the

Byzantine Empire The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantin ...

. It was applied to buildings in Syria in the 5th and 6th centuries and again in the 10th century. In

Constantinople la, Constantinopolis ota, قسطنطينيه , alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth ( Old Norse), Tsargrad ( Slavic), Qustantiniya (Arabic), Basileuousa ("Queen of Cities"), Megalopolis ( ...

's Myrelaion Church (c. 920), there are two oculi above the

stringcourse A belt course, also called a string course or sill course, is a continuous row or layer of stones or brick set in a wall. Set in line with window sills, it helps to make the horizontal line of the sills visually more prominent. Set between the fl ...

on both lateral facades.

Renaissance

Early examples of the oculus in

Renaissance architecture Renaissance architecture is the European architecture of the period between the early 15th and early 16th centuries in different regions, demonstrating a conscious revival and development of certain elements of ancient Greek and Roman thought ...

can be seen in

Florence Cathedral Florence Cathedral, formally the (; in English Cathedral of Saint Mary of the Flower), is the cathedral of Florence, Italy ( it, Duomo di Firenze). It was begun in 1296 in the Gothic style to a design of Arnolfo di Cambio and was structurally c ...

, in the nave

clerestory In architecture, a clerestory ( ; , also clearstory, clearstorey, or overstorey) is a high section of wall that contains windows above eye level. Its purpose is to admit light, fresh air, or both. Historically, ''clerestory'' denoted an upper ...

and topping the crowns of the arcade arches.

Neoclassical

Since the revival of dome construction beginning in the

Italian Renaissance The Italian Renaissance ( it, Rinascimento ) was a period in Italian history covering the 15th and 16th centuries. The period is known for the initial development of the broader Renaissance culture that spread across Europe and marked the tra ...

, open oculi have been replaced by light-transmitting

cupola In architecture, a cupola () is a relatively small, most often dome-like, tall structure on top of a building. Often used to provide a lookout or to admit light and air, it usually crowns a larger roof or dome. The word derives, via Italian, fr ...

s and other round windows, openings, and

skylights A skylight (sometimes called a rooflight) is a light-permitting structure or window, usually made of transparent or translucent glass, that forms all or part of the roof space of a building for daylighting and ventilation purposes. History Open ...

. They can be seen in the pediments of

Palladio Andrea Palladio ( ; ; 30 November 1508 – 19 August 1580) was an Italian Renaissance architect active in the Venetian Republic. Palladio, influenced by Roman and Greek architecture, primarily Vitruvius, is widely considered to be one of ...

's Villa Rotonda, though not in the dome. Use of oculus windows became more popular in

Baroque architecture Baroque architecture is a highly decorative and theatrical style which appeared in Italy in the early 17th century and gradually spread across Europe. It was originally introduced by the Catholic Church, particularly by the Jesuits, as a means t ...

. Widely used by

Neo-Palladian Palladian architecture is a European architectural style derived from the work of the Venetian architect Andrea Palladio (1508–1580). What is today recognised as Palladian architecture evolved from his concepts of symmetry, perspective an ...

architects including

Colen Campbell Colen Campbell (15 June 1676 – 13 September 1729) was a pioneering Scottish architect and architectural writer, credited as a founder of the Georgian style. For most of his career, he resided in Italy and England. As well as his architectura ...

, one can be seen in the dome of

Thomas Jefferson Thomas Jefferson (April 13, 1743 – July 4, 1826) was an American statesman, diplomat, lawyer, architect, philosopher, and Founding Father who served as the third president of the United States from 1801 to 1809. He was previously the nati ...

's Rotunda at the

University of Virginia The University of Virginia (UVA) is a public research university in Charlottesville, Virginia. Founded in 1819 by Thomas Jefferson, the university is ranked among the top academic institutions in the United States, with College admission ...

Examples

Dome of Pantheon (Rome).jpg, The

Ancient Roman In modern historiography, ancient Rome refers to Roman civilisation from the founding of the city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–509 B ...

oculus of the Pantheon (

Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus ( legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...

, Italy) Image:Plafond hasht behesht esfahan.jpg,

Islamic Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God (or ''Allah'') as it was revealed to Muhammad, the main ...

oculus opening into a

in the Hasht Behesht ( Isfahan,

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkm ...

) File:Gassicourt Sainte-Anne 327.JPG, Romanesque oculus of the Église Sainte-Anne de Gassicourt (

Mantes-la-Jolie Mantes-la-Jolie (, often informally called Mantes) is a commune in the Yvelines department in the Île-de-France region of north-central France. It is located to the west of Paris, from the centre of the capital. Mantes-la-Jolie is a subpre ...

, France) Cathédrale Notre-Dame de Laon, tour-lanterne 02.jpg,

Gothic Gothic or Gothics may refer to: People and languages *Goths or Gothic people, the ethnonym of a group of East Germanic tribes **Gothic language, an extinct East Germanic language spoken by the Goths **Crimean Gothic, the Gothic language spoken b ...

oculus in the

Laon Cathedral Laon Cathedral (french: Cathédrale Notre-Dame de Laon) is a Roman Catholic church located in Laon, Aisne, Hauts-de-France, France. Built in the twelfth and thirteenth centuries, it is one of the most important and stylistically unified exampl ...

(

Laon Laon () is a city in the Aisne department in Hauts-de-France in northern France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territori ...

, France) Cupola di santa maria del fiore dal campanile di giotto, 02.JPG,

Renaissance The Renaissance ( , ) , from , with the same meanings. is a period in European history marking the transition from the Middle Ages to modernity and covering the 15th and 16th centuries, characterized by an effort to revive and surpass id ...

oculus of the

(

Florence Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico ...

, Italy) Oculi - - Altar of Our Lady of Sweat - Duomo - Ravenna 2016.jpg, Baroque oculus in a dome of the Ravenna Cathedral (

Ravenna Ravenna ( , , also ; rgn, Ravèna) is the capital city of the Province of Ravenna, in the Emilia-Romagna region of Northern Italy. It was the capital city of the Western Roman Empire from 408 until its collapse in 476. It then served as the ca ...

, Italy) Parc de Bagatelle @ Paris (27765814394).jpg,

Rococo Rococo (, also ), less commonly Roccoco or Late Baroque, is an exceptionally ornamental and theatrical style of architecture, art and decoration which combines asymmetry, scrolling curves, gilding, white and pastel colours, sculpted moulding, ...

oculus in the Parc de Bagatelle (Paris) File:South gate of the Petit Trianon 004.JPG,

Louis XVI Louis XVI (''Louis-Auguste''; ; 23 August 175421 January 1793) was the last King of France before the fall of the monarchy during the French Revolution. He was referred to as ''Citizen Louis Capet'' during the four months just before he was e ...

round window of the

Petit Trianon The Petit Trianon (; French for "small Trianon") is a Neoclassical style château located on the grounds of the Palace of Versailles in Versailles, France. It was built between 1762 and 1768 during the reign of King Louis XV of France. ...

(

Versailles The Palace of Versailles ( ; french: Château de Versailles ) is a former royal residence built by King Louis XIV located in Versailles, about west of Paris, France. The palace is owned by the French Republic and since 1995 has been managed, ...

, France), with a

festoon A festoon (from French ''feston'', Italian ''festone'', from a Late Latin ''festo'', originally a festal garland, Latin ''festum'', feast) is a wreath or garland hanging from two points, and in architecture typically a carved ornament depict ...

-derived ornament at the top Georgsplatz 20, Fensterdetail, Hannover.jpg, Gothic Revival oculus of the Hannoversche Bank - Haus III on Georgstraße (

Hannover Hanover (; german: Hannover ; nds, Hannober) is the capital and largest city of the German state of Lower Saxony. Its 535,932 (2021) inhabitants make it the 13th-largest city in Germany as well as the fourth-largest city in Northern Germany ...

Germany Germany, officially the Federal Republic of Germany (FRG),, is a country in Central Europe. It is the most populous member state of the European Union. Germany lies between the Baltic and North Sea to the north and the Alps to the sou ...

) File:Opéra municipal de Clermont-Ferrand, œil de bœuf.jpg, 19th century Eclectic Classicist oculus of the Opéra-Théâtre de Clermont-Ferrand (

Clermont-Ferrand Clermont-Ferrand (, ; ; oc, label= Auvergnat, Clarmont-Ferrand or Clharmou ; la, Augustonemetum) is a city and commune of France, in the Auvergne-Rhône-Alpes region, with a population of 146,734 (2018). Its metropolitan area (''aire d'attra ...

, France) File:Fenêtre sur le toit du Palais de Justice.JPG, Beaux-Arts dormer oculus of the Building of Préfecture de Police de Paris (île de la Cité) Louis Baralis HSBC 1.jpg,

Art Nouveau Art Nouveau (; ) is an international style of art, architecture, and applied art, especially the decorative arts. The style is known by different names in different languages: in German, in Italian, in Catalan, and also known as the Moder ...

oculus of the Hôtel Élysée Palace (Paris) La Maison Bleue, porte d'entrée - Angers - 20110119.jpg,

Art Deco Art Deco, short for the French ''Arts Décoratifs'', and sometimes just called Deco, is a style of visual arts, architecture, and product design, that first appeared in France in the 1910s (just before World War I), and flourished in the Unit ...

oculus above a door in

Angers Angers (, , ) is a city in western France, about southwest of Paris. It is the prefecture of the Maine-et-Loire department and was the capital of the province of Anjou until the French Revolution. The inhabitants of both the city and the pr ...

(France)

References

External links

{{wiktionary-inline Ceilings Domes Roofs Windows Architectural elements