Citadels

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How people learned to build.

The studio takes its name and its standards from the long history of construction. These are fifteen of the places, and one machine, that changed what a builder could make. Every date and figure is cited; where historians disagree, we say so. The paintings are impressions made for this site, not photographs.

Firmitas, utilitas, venustas.

Strength, usefulness and beauty: the three qualities Vitruvius asked of a building, in De architectura, first century BCE.
  1. Painted impression of The Pyramids of Giza
    Painted impression, not a photographPlate 01

    Old Kingdom Egypt

    The Pyramids of Giza

    Giza plateau, Egypt.

    Geometry, held to a tolerance, at the scale of a mountain.

    • Three royal pyramids for the Fourth Dynasty kings Khufu, Khafre and Menkaure; Khufu's was built c. 2580–2560 BCE.
    • The Great Pyramid was originally about 146.6 m (280 royal cubits) tall, on sides of about 230 m (440 cubits).
    • Its faces rise at about 51°50′, a slope the builders expressed as a seked of 5½ palms.
    • It remained the tallest human-made structure for more than 3,700 years. Khafre's pyramid still keeps casing stones near its apex.

    Source: Wikipedia: Giza pyramid complex; Wikipedia: Great Pyramid of Giza

  2. Painted impression of Great Hypostyle Hall, Karnak
    Painted impression, not a photographPlate 02

    New Kingdom Egypt

    Great Hypostyle Hall, Karnak

    Temple of Amun-Ra, Karnak, Luxor (Egypt).

    Lift the roof in the middle, and the light comes in.

    • Built under Seti I (r. 1294–1279 BCE); his son Ramesses II completed the decoration.
    • 134 columns: twelve open-papyrus columns 21 m tall along the central aisle, and 122 closed-bud columns 15 m tall on either side.
    • The hall is 103 m across and 52 m deep.
    • Clerestory windows above the taller central aisle rose to a stone ceiling 24 m high.

    Source: Digital Karnak: Hypostyle Hall

  3. Painted impression of The Great Wall
    Painted impression, not a photographPlate 03

    Ancient to Ming China

    The Great Wall

    Northern China.

    Not one wall but centuries of walls, joined into one idea.

    • The first walls were built as early as the 7th century BCE; around 220 BCE Qin Shi Huang linked earlier walls together.
    • Most of what survives today was rebuilt under the Ming dynasty (1368–1644).
    • A five-year survey by China's State Administration of Cultural Heritage, published in 2012, measured all its walls at about 21,196 km.

    Source: Live Science: Great Wall of China twice as long as thought

  4. Painted impression of The Roman Forum
    Painted impression, not a photographPlate 04

    Roman Republic and Empire

    The Roman Forum

    Rome.

    A public square becomes a city's memory when it is rebuilt again and again.

    • The Temple of Saturn, whose columns stand in the foreground, was first dedicated around 497 BCE.
    • Under the Republic it housed the public treasury, the aerarium.
    • Its eight standing Ionic columns belong to a rebuilding after a fire; the inscription records that the Senate and People of Rome restored it.
    • Their granite came from Egypt: grey from Mons Claudianus and pink from Aswan.

    Source: World History Encyclopedia: Temple of Saturn, Rome

  5. Painted impression of Hagia Sophia
    Painted impression, not a photographPlate 05

    Byzantine

    Hagia Sophia

    Istanbul, Türkiye.

    A dome that seems to float on a ring of light.

    • Built for the emperor Justinian I by Anthemius of Tralles and Isidore of Miletus, and completed in 537.
    • Pendentives, curved triangles of masonry, carry the round dome over a square plan.
    • The dome is about 31.9 m across and 55.6 m above the floor, resting on a ring of 40 windows.
    • The first dome collapsed in 558 after earthquakes; Isidore the Younger rebuilt it with a steeper profile, about 6 m higher.

    Source: Princeton University: The Hagia Sophia; Hagia Sophia: the dome

  6. Painted impression of Great Mosque of Córdoba
    Painted impression, not a photographPlate 06

    Umayyad al-Andalus

    Great Mosque of Córdoba

    Córdoba, Spain.

    Repeat one good bay, and a room becomes a forest.

    • Abd al-Rahman I ordered its construction in 784; later rulers expanded it over some two hundred years.
    • The prayer hall has 856 columns of jasper, onyx, marble, granite and porphyry, many reused from Roman buildings.
    • Each bay carries a double arch, a horseshoe arch below and a round arch above, raising the ceiling over short columns.
    • The arches alternate red brick and white stone.

    Source: Mosqpedia: The Great Mosque at Córdoba; Lumen Learning: Great Mosque of Córdoba

  7. Painted impression of Cologne Cathedral
    Painted impression, not a photographPlate 07

    Gothic

    Cologne Cathedral

    Cologne, Germany.

    A good drawing can wait centuries for its builders.

    • The foundation stone was laid on 15 August 1248; work stopped around 1560 with the building unfinished.
    • The rediscovery of the original medieval plan for the façade led to work resuming in 1842.
    • Completed in 1880 to that medieval design, its north tower reaches 157.38 m; for four years it was the tallest building in the world.
    • Inscribed as a UNESCO World Heritage Site in 1996.

    Source: Wikipedia: Cologne Cathedral

  8. Painted impression of The Alhambra: Court of the Myrtles
    Painted impression, not a photographPlate 08

    Nasrid Granada

    The Alhambra: Court of the Myrtles

    Granada, Spain.

    Water as architecture: a still pool doubles every arch.

    • Begun under Ismaʿil I in the early 14th century; Yusuf I built the Comares Tower, and Muhammad V refurbished the court in 1362–1367.
    • The pool is 34 m long and 7.1 m wide, in a court about 36.6 m long.
    • The Comares Tower rises about 45 m, with walls 2 to 3 m thick. Its Hall of the Ambassadors is roofed by a wooden dome of 8,017 interlocking pieces.
    • Its walls carry poetry and Qur'anic verses carved in stucco, including a poem by Ibn Zamrak.

    Source: Wikipedia: Court of the Myrtles

  9. Painted impression of Dome of Florence Cathedral
    Painted impression, not a photographPlate 09

    Renaissance

    Dome of Florence Cathedral

    Florence, Italy.

    When the old method cannot work, invent the method.

    • Filippo Brunelleschi raised the dome between 1420 and 1436.
    • Two brick shells were built without wooden centering supporting them from below.
    • Herringbone brickwork passed the weight of fresh courses to the ribs as they were laid.
    • The work lifted some 37,000 tonnes of material, including over four million bricks.

    Source: Wikipedia: Florence Cathedral

  10. Painted impression of Machu Picchu
    Painted impression, not a photographPlate 10

    Inca

    Machu Picchu

    Cusco Region, Peru.

    Build with the mountain, not against it.

    • Built around 1450 as an estate for the Inca emperor Pachacuti, on a ridge 2,430 m above sea level.
    • Its finest buildings have polished dry-stone walls in the classic Inca style.
    • It was abandoned about a century later, at the time of the Spanish conquest.
    • Inscribed as a UNESCO World Heritage Site in 1983.

    Source: Wikipedia: Machu Picchu

  11. Painted impression of Süleymaniye Mosque
    Painted impression, not a photographPlate 11

    Ottoman

    Süleymaniye Mosque

    Istanbul, Türkiye.

    One dome at the centre of a whole city of service.

    • Designed by the imperial architect Mimar Sinan for Sultan Suleiman the Magnificent; founded in 1550 and inaugurated in 1557.
    • Its central dome is 26 m across and rises to 53 m.
    • Four minarets, each 76 m tall, stand at the corners of the courtyard.
    • The mosque sits within a charitable complex that included madrasas, a public kitchen and a hospital.

    Source: Wikipedia: Süleymaniye Mosque

  12. Painted impression of Shah Mosque
    Painted impression, not a photographPlate 12

    Safavid Persia

    Shah Mosque

    Naqsh-e Jahan Square, Isfahan, Iran.

    Turn the building, not the square.

    • Begun in 1611 for Shah Abbas I and completed around 1630, largely by the architect Ali Akbar Isfahani.
    • Its tiles use the haft rangi (seven-colour) method: several colours painted on each tile before firing, faster and cheaper than tile mosaic.
    • The outer dome rises to 52 m, with an inner dome of 38 m beneath it.
    • Because the square does not face Mecca, the entrance turns about 45 degrees so that the prayer hall does.
    • Part of the UNESCO World Heritage Site Meidan Emam, Esfahan, inscribed in 1979.

    Source: Wikipedia: Shah Mosque (Isfahan)

  13. Painted impression of Taj Mahal
    Painted impression, not a photographPlate 13

    Mughal India

    Taj Mahal

    Agra, India.

    Symmetry, held perfectly, until it feels like calm.

    • Built by the Mughal emperor Shah Jahan in memory of his wife Mumtaz Mahal; the main architect was Ustad Ahmad Lahori.
    • The tomb was finished in 1648; the mosque, guest house, gateway and courtyards in 1653.
    • Brick in lime mortar, faced with white marble and red sandstone, and inlaid with flowers of precious and semi-precious stones.
    • Masons, inlayers, calligraphers and dome builders came from across the empire, Central Asia and Iran.

    Source: UNESCO World Heritage List: Taj Mahal

  14. Elevation, not to scalePlate 14

    Industrial

    The Crystal Palace

    Hyde Park, London.

    Design the module and the building assembles itself.

    • Designed by Joseph Paxton for the Great Exhibition of 1851.
    • Cast iron and plate glass on a grid of identical, prefabricated 24-foot modules.
    • About 293,000 panes of glass; the building was finished in thirty-nine weeks.

    Source: Wikipedia: The Crystal Palace

  15. Elevation, not to scalePlate 15

    Industrial

    Eiffel Tower

    Paris.

    Thousands of parts, each one drawn before it was made.

    • Assembled in two years, two months and five days for the 1889 Exposition Universelle.
    • 18,038 iron parts joined by about 2.5 million rivets.
    • Originally 312 m (1,024 ft) tall without antennas.

    Source: Official site of the Eiffel Tower: key figures

  16. Elevation, not to scalePlate 16

    Digital

    Sketchpad

    MIT Lincoln Laboratory.

    The drawing became the building material.

    • Written by Ivan Sutherland for his PhD thesis, on the TX-2 computer.
    • Users drew directly on the screen with a light pen and set geometric constraints between lines.
    • Regarded as the ancestor of modern CAD and the first program with a complete graphical user interface.

    Source: Wikipedia: Sketchpad