Editing Oculus (architecture)

{{Short description|Circular opening in the center of a dome or in a wall}}
{{Redirect|Oculi|the third Sunday in Lent|Lent{{!}}Oculi Sunday}}
[[File:Paris - Palais du Louvre - PA00085992 - 226 (oculus cropped).jpg|thumb|upright=1.35|[[Renaissance architecture|Renaissance]] oculus on the west facade of the [[Cour Carrée]] of the [[Louvre Palace]], with figures of war and peace, sculpted by [[Jean Goujon]] and designed by [[Pierre Lescot]], 1548<ref>{{cite book|last=Bresc-Bautier|first=Geneviève|title=The Louvre, a Tale of a Palace|date=2008|publisher=Musée du Louvre Éditions|isbn=978-2-7572-0177-0|page=122|url=}}</ref>]]

An '''oculus''' ({{etymology|la|{{wikt-lang|la|oculus}}|eye}}; {{plural abbr|'''oculi'''}}) is a circular opening in the center of a [[dome]] or in a wall. Originating in [[classical architecture]], it is a feature of [[Byzantine architecture|Byzantine]] and [[Neoclassical architecture]]. 

A horizontal oculus in the center of a dome is also called '''opaion''' ({{etymology|grc|''{{wikt-lang|grc|ὀπαῖον}}'' ({{grc-transl|ὀπαῖον}})|(smoke) hole}}; {{plural abbr|'''opaia'''}}).

==Oeil-de-boeuf==
{{wiktionary | œil-de-bœuf}}
An '''''oeil-de-boeuf''''' ({{IPA|fr|œj.də.bœf|lang}}; {{langx|en|"bull's eye"}}), also '''''œil de bœuf''''' and sometimes anglicized as '''''ox-eye window''''', is a relatively small [[ellipse|elliptical]]  [[window]], typically for an upper storey, and sometimes set in a roof slope as a [[dormer]], or above a door to let in [[Daylighting (architecture)|natural light]]. These are relatively small windows, traditionally oval. The term is increasingly used for circular windows (in which case it could also be called an oculus), but not for holes in domes or ceilings.<ref name=riba>{{cite web|title=Oculus window |url=http://www.architecture.com/LibraryDrawingsAndPhotographs/Palladio/PalladianBritain/PalladianInteriors/PalladianPrinciples/Light/OculusWindow.aspx |archive-url=https://web.archive.org/web/20140327234516/http://www.architecture.com/LibraryDrawingsAndPhotographs/Palladio/PalladianBritain/PalladianInteriors/PalladianPrinciples/Light/OculusWindow.aspx |url-status=dead |archive-date=March 27, 2014 |date=March 27, 2014|website= Royal Institute of British Architects|access-date= 24 January 2014}}</ref>

Windows of this type are commonly found in the grand architecture of [[baroque architecture|Baroque]] [[France]]. The term is also applied to similar round windows, such as those found in [[Georgian architecture]] in Great Britain, and later [[Greek Revival architecture|Greek Revival]] and [[Colonial Revival architecture|Colonial Revival]] styles in North America, so that must be considered part of the usage. The term initially applied to horizontal elliptical windows, but is also used for vertical ones.<ref>Burden, Ernest E., ''Illustrated dictionary of architecture'', McGraw-Hill Professional, 2001, p.354, {{ISBN|0-07-137529-5}}, {{ISBN|978-0-07-137529-0}}
[https://books.google.com/books?id=EGurZuDLZGUC&dq=Oeil-de-boeuf+window&pg=PA354 Google Books]</ref>

The spread is not limited to [[ecclesiastical]] architecture. This type of window can also be found in the late Romanesque period in the area of secular architecture in the castles of [[Frederick II, Holy Roman Emperor|Frederick II]] of Hohenstaufen, Holy Roman Emperor from 1220 to 1250, ([[Castel del Monte, Apulia|Castel del Monte]], [[Palazzo San Gervasio]], on the donjon in the castle of Lucera, etc.), later also in [[Renaissance architecture|Renaissance]] palaces and villas and in the Baroque.

<gallery>
File:Schloss Chenonceau Ochsenauge.jpg|An ''oeil-de-boeuf'' window of the ''[[Château de Chenonceau]]'', France
File:Un œil de bœuf à Lyon (France).JPG|An "œil de bœuf" window in [[Lyon]] (France)
File:Sutton Lodge, Brighton Rd, SUTTON, Surrey, Greater London (4).jpg|An ''oeil-de-boeuf'' window in the [[Georgian architecture|Georgian]] Sutton Lodge in [[Sutton, London]].<ref>[http://home2.btconnect.com/suttonlodge/history.php Sutton Lodge Day Centre website]</ref>
</gallery>

==History==
===Classical===
The oculus was used in [[Ancient Roman architecture]], one of the finest examples being that in the dome of the [[Pantheon, Rome]]. 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 {{convert|8.7|m|ft|abbr=in}}, allowing it to light the building.

===Byzantine===
The oculus was widely used in the architecture of the [[Byzantine Empire]]. It was applied to buildings in [[Syria]] in the 5th and 6th centuries and again in the 10th century. In [[Constantinople]]'s [[Bodrum Mosque|Myrelaion Church]] (c. 920), there are two oculi above the [[stringcourse]] on both lateral facades.<ref name="ĆurčićJohnson2012">{{cite book|last1=Ćurčić|first1=Slobodan |last2=Johnson|first2=Mark Joseph |last3=Ousterhout|first3=Robert G. |last4=Papalexandrou|first4=Amy |title=Approaches to Byzantine Architecture and Its Decoration: Studies in Honor of Slobodan Ćurčić |url={{GBurl|id=b5eKujogjYAC|p=148}} |access-date=24 January 2013 |date=1 January 2012 |publisher=Ashgate Publishing |isbn=978-1-4094-2740-7 |pages=148–}}</ref>

===Renaissance===
Early examples of the oculus in [[Renaissance architecture]] can be seen in [[Florence Cathedral]], in the nave [[clerestory]] and topping the crowns of the arcade arches.<ref>{{cite web|title=The Cathedral of Santa Maria del Fiore, Florence|url=http://arts.muohio.edu/faculty/benson/florencecathedral/|archive-url=https://web.archive.org/web/20140327234826/http://arts.muohio.edu/faculty/benson/florencecathedral/|url-status=dead|archive-date=March 27, 2014|date=March 27, 2014|access-date= 24 January 2013|website=muohio.edu}}</ref>

===Neoclassical===
Since the revival of dome construction beginning in the [[Italian Renaissance]], open oculi have been replaced by light-transmitting [[cupola]]s and other round windows, openings, and [[skylight (window)|skylights]]. They can be seen in the pediments of [[Palladio]]'s [[Villa Rotonda]], though not in the dome. Use of oculus windows became more popular in [[Baroque architecture]]. Widely used by [[Neo-Palladian]] architects including [[Colen Campbell]], one can be seen in the dome of [[Thomas Jefferson]]'s [[The Rotunda (University of Virginia)|Rotunda]] at the [[University of Virginia]].<ref name=riba/><ref>{{cite web|url=http://www.arch.virginia.edu/archive/ded7y/vs98/RCstudy1.htm|title=Daylighting in two centroidal spaces at the University of Virginia: Case Study, The Rotunda and Caplin Pavilion|website=The [[University of Virginia]]|access-date=24 January 2013|archive-date=28 March 2014|archive-url=https://web.archive.org/web/20140328010912/http://www.arch.virginia.edu/archive/ded7y/vs98/RCstudy1.htm|url-status=dead}}</ref>

==Examples==
{{center|''Short visual history of oculli''}}

<gallery widths="170px" heights="220px" mode=packed>

2024 Pantheon Rome 04 2024 7134.jpg|The [[Ancient Roman architecture|Ancient Roman]] oculus (opaion) of the [[Pantheon (Rome)|Pantheon]], [[Rome]], Italy

Image:Plafond hasht behesht esfahan.jpg|[[Islamic architecture|Islamic]] oculus (opaion) opening into a [[cupola]] in the [[Hasht Behesht]], [[Isfahan]], [[Iran]]

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

File:Gassicourt Sainte-Anne 327.JPG|[[Romanesque architecture|Romanesque]] oculus of the {{ill|Église Sainte-Anne de Gassicourt|fr}}, [[Mantes-la-Jolie]], France

Cathédrale Notre-Dame de Laon, tour-lanterne 02.jpg|[[Gothic architecture|Gothic]] oculus in the [[Laon Cathedral]], [[Laon]], France

Florence duomo fc10.jpg|[[Renaissance architecture|Renaissance]] oculus of the [[Florence Cathedral]], [[Florence]], Italy

Parc de Bagatelle @ Paris (27765814394).jpg|[[Rococo]] oculus in the Parc de Bagatelle (Paris)

File:South gate of the Petit Trianon 004.JPG|[[Louis XVI style|Louis XVI]] round window of the [[Petit Trianon]] ([[Versailles]], France), with a [[festoon]]-derived ornament at the top

Georgsplatz 20, Fensterdetail, Hannover.jpg|[[Gothic Revival architecture|Gothic Revival]] oculus of the Hannoversche Bank - Haus III on Georgstraße, [[Hannover]], [[Germany]]

File:Opéra municipal de Clermont-Ferrand, œil de bœuf.jpg|19th century [[Eclecticism in architecture|Eclectic]] Classicist oculus of the {{ill|Opéra-Théâtre de Clermont-Ferrand|fr}}, [[Clermont-Ferrand]], France

File:Fenêtre sur le toit du Palais de Justice.JPG|[[Beaux-Arts architecture|Beaux-Arts]] [[dormer]] oculus of the Building of Préfecture de Police de Paris, Île de la Cité

Louis Baralis HSBC 1.jpg|[[Art Nouveau]] oculus of the {{ill|Hôtel Élysée Palace|fr}}, Paris

La Maison Bleue, porte d'entrée - Angers - 20110119.jpg|[[Art Deco#Architecture|Art Deco]] oculus above a door in [[Angers]], France
</gallery>

==References==
{{reflist}}

==External links==
{{Commons category|Oculi}}
{{wiktionary-inline|oculus}}

[[Category:Ceilings]]
[[Category:Domes]]
[[Category:Roofs]]
[[Category:Windows]]
[[Category:Architectural elements]]