Editing Hagia Sophia (section)

==Architecture==
[[File:Hagia-Sophia-Grundriss.jpg|thumb|upright=1.2<!--size for detailed plan-->|a) Plan of the gallery (upper half)<br />b) Plan of the ground floor (lower half)]]

Hagia Sophia is one of the greatest surviving examples of [[Byzantine architecture]].<ref name="BAT" /> Its interior is decorated with [[mosaic]]s, [[marble]] pillars, and coverings of great artistic value. Justinian had overseen the completion of the greatest cathedral ever built up to that time, and it was to remain the largest cathedral for 1,000 years until the completion of the [[Seville Cathedral|cathedral in Seville]] in Spain.<ref>{{cite book |title=Religions of the World: A Comprehensive Encyclopedia of Beliefs and Practices |first1=J. Gordon |last1=Melton |first2=Martin |last2=Baumann |publisher=ABC-CLIO |date=2010 |page=513}}</ref>

The Hagia Sophia uses masonry construction. The structure has brick and [[Mortar (masonry)|mortar]] joints that are 1.5 times the width of the bricks. The mortar joints are composed of a combination of sand and minute ceramic pieces distributed evenly throughout the mortar joints. This combination of sand and [[potsherds]] was often used in [[Roman concrete]], a predecessor to modern [[concrete]]. A considerable amount of iron was used as well, in the form of cramps and ties.<ref>{{Cite journal |last1=Syrmakezis |first1=K. |last2=Mavrouli |first2=O. |last3=Papaevaggeliou |first3=P. |last4=Aggelakopolulou |first4=E. |last5=Bakolas |first5=A. |last6=Moropoulou |first6=A. |date=November 2013 |title=Finite element analysis and fragility curves for the evaluation of restoration mortars behavior regarding the earthquake protection of historic structures |journal=Soil Dynamics and Earthquake Engineering |volume=54 |pages=61–65 |doi=10.1016/j.soildyn.2013.07.002 |bibcode=2013SDEE...54...61S |issn=0267-7261}}</ref>

Justinian's basilica was at once the culminating architectural achievement of [[Late Antiquity|late antiquity]] and the first masterpiece of Byzantine architecture. Its influence, both architecturally and liturgically, was widespread and enduring in the [[Eastern Christianity]], [[Western Christianity]], and [[Islam]] alike.<ref name="Sqour-2016">{{Cite conference |last=Sqour |first=Saqer |date=5–6 May 2016 |title=Influence of Hagia Sophia on the Construction of Dome in Mosque Architecture |url=https://www.openacessjournal.com/article-file/20201028591156621912influ.pdf |conference=8th International Conference on Latest Trends in Engineering and Technology (ICLTET'2016) |archive-url=https://ghostarchive.org/archive/20221009/https://www.openacessjournal.com/article-file/20201028591156621912influ.pdf |archive-date=2022-10-09 |url-status=live}}</ref><ref>{{Cite journal |last=Ousterhout |first=Robert |date=1996-01-01 |title=An Apologia for Byzantine Architecture |url=https://www.journals.uchicago.edu/doi/10.2307/767224 |journal=Gesta |volume=35 |issue=1 |pages=21–33 |doi=10.2307/767224 |jstor=767224 |s2cid=193354724 |issn=0016-920X}}</ref>

[[File:Hagia Sophia Segment.svg|thumb|left|Cutaway isometric projection]]
The vast interior has a complex structure. The [[nave]] is covered by a central dome which at its maximum is {{cvt|55.6|m|ftin||sp=us}} from floor level and rests on an arcade of 40 arched windows. Repairs to its structure have left the dome somewhat elliptical, with the diameter varying between {{cvt|31.24|and|30.86|m|ftin|sp=us}}.<ref>{{cite journal |last1=Plachý |first1=Jan |last2=Musílek |first2=Josef |last3=Podolka |first3=Luboš |last4=Karková |first4=Monika |title=Disorders of the Building and its Remediation – Hagia Sophia, Turkey the Most the Byzantine Building |journal=Procedia Engineering |date=2016 |volume=161 |pages=2259–2264 |doi=10.1016/j.proeng.2016.08.825 |doi-access=free}}</ref>

At the western entrance and eastern liturgical side, there are arched openings extended by half domes of identical diameter to the central dome, carried on smaller [[semi-dome]]d [[exedrae]], a hierarchy of dome-headed elements built up to create a vast oblong interior crowned by the central dome, with a clear span of {{cvt|76.2|m|ft|sp=us}}.<ref name=BAT />[[File:Hagia sophia mathematische Konstruktion.jpg|thumb|The geometric conception is based on mathematical formulas of Heron of Alexandria. It avoids use of irrational numbers for the construction]]The theories of [[Hero of Alexandria]], a [[Hellenistic mathematics|Hellenistic mathematician]] of the 1st century AD, may have been utilized to address the challenges presented by building such an expansive dome over so large a space.<ref>{{Cite web |title=Helge Svenshon 2010: Das Bauwerk als "Aistheton Soma" – Eine Neuinterpretation der Hagia Sophia im Spiegel antiker Vermessungslehre und angewandter Mathematik. In: Falko Daim · Jörg Drauschke (Hrsg.) Byzanz – das Römerreich im Mittelalter Teil 2, 1 Schauplätze, Römisch-Germanisches Zentralmuseum Forschungsinstitut für Vor- und Frühgeschichte |url=http://tuprints.ulb.tu-darmstadt.de/4483/1/Byzanz_Sonderdruck_Svenshon.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://tuprints.ulb.tu-darmstadt.de/4483/1/Byzanz_Sonderdruck_Svenshon.pdf |archive-date=2022-10-09 |url-status=live |access-date=15 July 2020}}</ref> Svenshon and Stiffel proposed that the architects used Hero's proposed values for constructing vaults. The square measurements were calculated using the side-and-diagonal number progression, which results in squares defined by the numbers 12 and 17, wherein 12 defines the side of the square and 17 its diagonal, which have been used as standard values as early as in cuneiform Babylonian texts.<ref name="Svenshon">Svenshon, Helge Olaf: Heron of Alexandria and the Dome of Hagia Sophia in Istanbul. In: Proceedings of the Third Congress on Construction History. Brandenburg University of Technology Cottbus, 20th – 24th May 2009. NEUNPLUS1, Berlin, S. 1387–1394. {{ISBN|978-3-936033-31-1}}</ref>

Each of the four sides of the great square Hagia Sophia is approximately 31&nbsp;m long,<ref>{{Cite book |last=Schibille |first=Nadine |url=https://books.google.com/books?id=n-oGDAAAQBAJ |title=Hagia Sophia and the Byzantine Aesthetic Experience |date=2016-04-22 |publisher=Routledge |isbn=978-1-317-12415-3 |language=en}}</ref> and it was previously thought that this was the equivalent of 100 [[Byzantine foot|Byzantine feet]].<ref name="Svenshon" /> Svenshon suggested that the size of the side of the central square of Hagia Sophia is not 100 Byzantine feet but instead 99 feet. This measurement is not only rational, but it is also embedded in the system of the side-and-diagonal number progression (70/99) and therefore a usable value by the applied mathematics of antiquity. It gives a diagonal of 140 which is manageable for constructing a huge dome.<ref>{{Cite web |last=Stiftung |first=Gerda Henkel |title=Die Hagia Sophia Justinians – Mathematischer Raum als Bühne des Kaisers |url=https://lisa.gerda-henkel-stiftung.de/die_hagia_sophia_justinians_mathematischer_raum_als_buehne_des_kaisers?nav_id=3486 |website=L.I.S.A. WISSENSCHAFTSPORTAL GERDA HENKEL STIFTUNG}}</ref>

===Floor===
[[File:Hagia Sophia - Omphalion - Ayasofya - Αγία Σοφία - 47856233651.jpg|thumb|The [[Omphalion]], a marble section of the floor in Hagia Sophia, is the place where Byzantine emperors have been crowned. The stone floor of the Hagia Sophia dates from the 6th century.]]

The stone floor of Hagia Sophia dates from the 6th century. After the first collapse of the vault, the broken dome was left ''in situ'' on the original Justinianic floor and a new floor was laid above the rubble when the dome was rebuilt in 558.<ref name="Dark-2019b">{{Cite book |last1=Dark |first1=Ken R. |url=https://books.google.com/books?id=TU7lswEACAAJ |title=Hagia Sophia in Context: An Archaeological Re-examination of the Cathedral of Byzantine Constantinople |last2=Kostenec |first2=Jan |publisher=Oxbow Books |year=2019 |isbn=978-1-78925-030-5 |location=Oxford |pages=69–72 |language=en}}</ref> From the installation of this second Justinianic floor, the floor became part of the [[liturgy]], with significant locations and spaces demarcated in various ways using different-coloured stones and marbles.<ref name="Dark-2019b" />

The floor is predominantly made up of [[Proconnesian marble]], quarried on [[Proconnesus]] (Marmara Island) in the [[Propontis]] (Sea of Marmara). This was the main white marble used in the monuments of Constantinople. Other parts of the floor, like the Thessalian [[verd antique]] "marble", were quarried in [[Ancient Thessaly|Thessaly]] in [[Roman Greece]]. The Thessalian verd antique bands across the nave floor were often likened to rivers.<ref>{{Cite journal |last=Majeska |first=George P. |date=1978 |title=Notes on the Archeology of St. Sophia at Constantinople: The Green Marble Bands on the Floor |journal=Dumbarton Oaks Papers |volume=32 |pages=299–308 |doi=10.2307/1291426 |jstor=1291426 |issn=0070-7546}}</ref>

The floor was praised by numerous authors and repeatedly compared to a sea.<ref name="Barry-2007" /> The Justinianic poet [[Paul the Silentiary]] likened the ambo and the solea connecting it to the sanctuary with an island in a sea, with the sanctuary itself a harbour.<ref name="Barry-2007" /> The 9th-century ''Narratio'' writes of it as "like the sea or the flowing waters of a river".<ref name="Barry-2007" /> [[Michael the Deacon]] in the 12th century also described the floor as a sea in which the ambo and other liturgical furniture stood as islands.<ref name="Barry-2007" /> During the 15th-century conquest of Constantinople, the Ottoman caliph Mehmed is said to have ascended to the dome and the galleries in order to admire the floor, which according to [[Tursun Beg]] resembled "a sea in a storm" or a "petrified sea".<ref name="Barry-2007" /> Other Ottoman-era authors also praised the floor; [[Tâcîzâde Cafer Çelebi]] compared it to waves of marble.<ref name="Barry-2007" /> The floor was hidden beneath a carpet on 22 July 2020.<ref name="BBC News-2020b" />

===Narthex and portals===
The Imperial Gate, or Imperial Door, was the main entrance between the exo- and esonarthex, and it was originally exclusively used by the emperor.<ref>{{Cite journal |last=Teteriatnikov |first=Natalia |title=Devotional Crosses in the Columns and Walls of Hagia Sophia |date=1998 |url=https://www.jstor.org/stable/44172340 |journal=Byzantion |volume=68 |issue=2 |pages=419–445 |jstor=44172340 |issn=0378-2506}}</ref><ref name="Opstall-2018">{{Cite book |last=Opstall |first=Emilie M. van |date=2018-06-28 |chapter=On the Threshold: Paul the Silentiary's Ekphrasis of Hagia Sophia |url=https://brill.com/view/book/9789004369009/BP000010.xml |title=Sacred Thresholds: The Door to the Sanctuary in Late Antiquity |language=en |pages=31–65 |doi=10.1163/9789004369009_003 |isbn=9789004369009|s2cid=201516637|oclc=1037899166}}</ref> A long ramp from the northern part of the outer narthex leads up to the upper gallery.<ref>{{Cite web |date=2023-04-10 |title=Hagia Sophia Imperial Gate {{!}} Visit & Explore The Iconic Landmark |url=https://hagiasophiatickets.com/imperial-gate |access-date=2023-07-18 |website=Hagia Sophia Tickets |language=en}}</ref>[[File:Istanbul.Hagia Sophia055.jpg|thumb|right|West side of the upper gallery]]

===Upper gallery===
[[File:Istanbul - Hagia Sophia - slope to first floor.jpg|upright|thumb|left|Slope leading to the upper gallery in the Hagia Sophia]]

The upper gallery, or [[matroneum]], is horseshoe-shaped; it encloses the nave on three sides and is interrupted by the apse. Several mosaics are preserved in the upper gallery, an area traditionally reserved for the Empress and her court. The best-preserved mosaics are located in the southern part of the gallery.

The northern first floor gallery contains [[Runic inscriptions in Hagia Sophia|runic graffiti]] believed to have been left by members of the [[Varangian Guard]].<ref>{{Cite book |last=Mel'nikova |first=Elena A. |url=http://worldcat.org/oclc/1233690226 |title=A New Runic Inscription from Hagia Sophia Cathedral in Istanbul |date=2016 |publisher=Institute of World History, Russian Academy of Sciences, Moscow |oclc=1233690226}}</ref> Structural damage caused by natural disasters is visible on the Hagia Sophia's exterior surface. To ensure that the Hagia Sophia did not sustain any damage on the interior of the building, studies have been conducted using ground penetrating radar within the gallery of the Hagia Sophia. With the use of [[ground-penetrating radar]] (GPR), teams discovered weak zones within the Hagia Sophia's gallery and also concluded that the curvature of the vault dome has been shifted out of proportion, compared to its original angular orientation.<ref>{{Cite journal |last1=Yalçıner |first1=Cahit Çağlar |last2=Kurban |first2=Yunus Can |last3=Altunel |first3=Erhan |date=May 2017 |title=Research using GPR into the cause of cracks and depressions in the floor of the gallery of Hagia Sophia Museum |journal=Construction and Building Materials |volume=139 |pages=458–66 |doi=10.1016/j.conbuildmat.2017.02.036 |issn=0950-0618}}</ref>

===Dome===
[[File:Istanbul asv2021-10 img22 Hagia Sophia.jpg|thumb|View of the dome interior]]

The [[dome]] of Hagia Sophia has spurred particular interest for many art historians, architects, and engineers because of the innovative way the original architects envisioned it. The dome is carried on four spherical triangular [[pendentive]]s, making the Hagia Sophia one of the first large-scale uses of this element. The pendentives are the corners of the square base of the dome, and they curve upwards into the dome to support it, thus restraining the lateral forces of the dome and allowing its weight to flow downwards.<ref>Kleiner and Mamiya. ''Gardner's Art Through the Ages'', p. 331.</ref><ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/449698/pendentive |title=pendentive (architecture) – Britannica Online Encyclopedia |encyclopedia=Britannica.com |access-date=4 December 2011}}</ref> The main dome of the Hagia Sophia was the largest pendentive dome in the world until the completion of [[St Peter's Basilica]], and it has a much lower height than any other dome of such a large diameter.

The great dome at the Hagia Sophia is {{convert|32.6|m}} in diameter and is only {{convert|0.61|m}} thick. The main building materials for the original Hagia Sophia were brick and mortar. Brick aggregate was used to make roofs easier to construct. Due to the material's plasticity, it was chosen over cut stone due to the fact that aggregate can be used over a longer distance.<ref>{{Cite journal |last=MacDonald |first=William |date=1957 |title=Design and Technology in Hagia Sophia |journal=Perspecta |volume=4 |pages=20–27 |doi=10.2307/1566853 |issn=0079-0958 |jstor=1566853}}</ref> According to Rowland Mainstone, "it is unlikely that the vaulting-shell is anywhere more than one normal brick in thickness".<ref>{{Cite book |last=Mainstone |first=Rowland J. |url=https://books.google.com/books?id=jSw7FSSrd8AC |title=Hagia Sophia: Architecture, Structure, and Liturgy of Justinian's Great Church |date=1997 |publisher=Thames and Hudson |isbn=978-0-500-27945-8 |pages=81 |language=en}}</ref>

The weight of the dome remained a problem for most of the building's existence. The original cupola collapsed entirely after the earthquake of 558; in 563 a new dome was built by [[Isidore the Younger]]. Unlike the original, this included 40 ribs and was raised 6.1 meters (20 feet), in order to lower the lateral forces on the church walls. A larger section of the second dome collapsed as well, over two episodes, so that as of 2021, only two sections of the present dome, the north and south sides, are from the 562 reconstructions. Of the whole dome's 40 ribs, the surviving north section contains eight ribs, while the south section includes six ribs.<ref>{{cite book |last=Mainstone |first=Rowland J. |title=Hagia Sophia |year=2001 |publisher=Thames & Hudson |location=London |isbn=978-0-500-27945-8 |pages=90–93}}</ref>

Although this design stabilizes the dome and the surrounding walls and arches, the actual construction of the walls of Hagia Sophia weakened the overall structure. The [[bricklayer]]s used more [[Mortar (masonry)|mortar]] than brick, which is more effective if the mortar was allowed to settle, as the building would have been more flexible; however, the builders did not allow the mortar to cure before they began the next layer. When the dome was erected, its weight caused the walls to lean outward because of the wet mortar underneath. When Isidore the Younger rebuilt the fallen cupola, he had first to build up the interior of the walls to make them vertical again. Additionally, the architect raised the height of the rebuilt dome by approximately {{cvt|6|metres|feet}} so that the lateral forces would not be as strong and its weight would be transmitted more effectively down into the walls. Moreover, he shaped the new cupola like a [[scallop]]ed shell or the inside of an umbrella, with [[Ogival arch|ribs]] that extend from the top down to the base. These ribs allow the weight of the dome to flow between the windows, down the pendentives, and ultimately to the foundation.<ref name="Mainstone-1988">{{Cite book |title=Hagia Sophia: Architecture, structure, and liturgy of Justinian's great church |last=Mainstone |first=R.J. (Rowland J.) |date=1988 |publisher=Thames and Hudson |isbn=978-0-500-34098-1 |location=New York |oclc=15378795}}</ref>

Hagia Sophia is famous for the light that reflects everywhere in the interior of the nave, giving the dome the appearance of hovering. This effect was achieved by inserting forty windows around the base of the original structure, which also reduced its weight.<ref name="Mainstone-1988" />

===Buttresses===
Numerous [[buttress]]es have been added throughout the centuries. The [[flying buttress]]es to the west of the building, although thought to have been constructed by the Crusaders upon their visit to Constantinople, were actually built during the Byzantine era. This shows that the Romans had prior knowledge of flying buttresses, which can also be seen at in Greece, at the [[Arch of Galerius and Rotunda|Rotunda of Galerius]] in [[Thessaloniki]], at the monastery of [[Hosios Loukas]] in [[Boeotia]], and in Italy at the octagonal basilica of [[Basilica of San Vitale|San Vitale]] in [[Ravenna]].<ref name="Mainstone-1988" /><ref>{{Cite journal |last=Machabee |first=Stephanie |date=2022-04-01 |title=Religion and Contested Cultural Heritage: The Rotunda and Hagia Sophia as Church, Mosque, and Museum |url=https://elischolar.library.yale.edu/gsas_dissertations/630/ |journal=Yale Graduate School of Arts and Sciences Dissertations}}</ref> Other buttresses were constructed during the Ottoman times under the guidance of the architect [[Mimar Sinan|Sinan]]. A total of 24 buttresses were added.<ref>{{cite web |url=http://ayasofyamuzesi.gov.tr/en/ext-buttresses |title=Buttresses {{!}} Hagia Sophia Museum |website=ayasofyamuzesi.gov.tr |publisher=Directorate of Hagia Sophia Museum |access-date=18 April 2017 |archive-date=28 August 2019 |archive-url=https://web.archive.org/web/20190828112435/https://ayasofyamuzesi.gov.tr/en/ext-buttresses |url-status=dead}}</ref>

===Minarets===
[[File:Aya Sophia (7144824757).jpg|thumb|Minarets of Hagia Sophia]]

The [[minaret]]s were an Ottoman addition and not part of the original church's Byzantine design. Mehmed had built a wooden minaret over one of the half domes soon after Hagia Sophia's conversion from a cathedral to a mosque. This minaret does not exist today. One of the minarets (at southeast) was built from red brick and can be dated back from the reign of Mehmed or his successor [[Bayezid II|Beyazıd II]]. The other three were built from white limestone and sandstone, of which the slender northeast column was erected by Bayezid II and the two identical, larger minarets to the west were erected by [[Selim II|Selim&nbsp;II]] and designed by the famous Ottoman architect [[Mimar Sinan]]. Both are {{cvt|60|metres|feet}} in height, and their thick and massive patterns complete Hagia Sophia's main structure. Many ornaments and details were added to these minarets on repairs during the 15th, 16th, and 19th centuries, which reflect each period's characteristics and ideals.<ref>{{cite web |author=Hagia Sophia |url=http://www.hagiasophia.com/listingview.php?listingID=7 |title=Mosque |access-date=26 February 2013 |archive-url=https://web.archive.org/web/20130128085515/http://www.hagiasophia.com/listingview.php?listingID=7 |archive-date=28 January 2013 |url-status=dead}}</ref><ref>{{Cite web |url=http://ayasofyamuzesi.gov.tr/en/ext-minarets |title=Minarets &#124; Hagia Sophia Museum |access-date=20 November 2017 |archive-date=30 March 2019 |archive-url=https://web.archive.org/web/20190330205331/https://ayasofyamuzesi.gov.tr/en/ext-minarets |url-status=dead}}</ref>