Ancient City Planning
The Planned City as a Political Act
Cities do not plan themselves. Every grid, every forum, every ceremonially aligned processional street reflects a decision — about power, about the relationship between the individual and the state, about what a city is for. The history of ancient city planning is inseparable from the history of political authority, because the power to reshape the urban landscape and compel thousands of people to build according to a predetermined design has always required extraordinary resources and legitimacy.
The earliest evidence of deliberate urban planning appears in the cities of the Indus Valley Civilisation during the 3rd millennium BC. At Mohenjo-daro in modern Pakistan, a grid of streets oriented roughly north-south and east-west divides the lower city into blocks. Houses had standardised features: baked-brick construction, private bathrooms draining into a municipal sewage system, and courtyards. The degree of standardisation implies either strong central authority or powerful social conventions — which mechanism produced this order remains one of the great unsolved problems of South Asian archaeology.
Hippodamian Planning and the Greek Grid
In the Greek world, systematic grid planning is associated above all with Hippodamos of Miletus, a 5th-century BC theorist whom Aristotle credited with inventing the idea of dividing a city into functional zones. Hippodamos is said to have planned the Piraeus, the port of Athens, and Thurii in southern Italy; his ideas influenced the layout of Rhodes, founded in 408 BC, and Priene in Asia Minor.
Priene is the best-preserved Hippodamian city. Founded around the mid-4th century BC on a steep hillside above the Maeander plain, it imposed a rigid grid regardless of topography: streets ran east-west across the slope, with north-south cross-streets climbing steeply via steps. The grid created roughly equal insulae (city blocks) of standardised size. The agora — the civic and commercial heart — occupied a central position, flanked by colonnaded stoas. The sanctuary of Athena Polias, the bouleuterion (council chamber), and the theatre were each assigned their own block. The result was a city that made its social hierarchy legible in its layout.
The agora itself deserves attention as an urban form. Unlike the Roman forum, which evolved toward a more enclosed, hierarchically organised ceremonial space, the Greek agora was initially a more flexible gathering place — for assemblies, markets, law courts, and philosophical debate. The agora of Athens accumulated buildings over centuries: the Stoa Poikile (Painted Stoa), the Royal Stoa, the Stoa of Attalos (reconstructed in the 1950s and still standing), the Temple of Hephaestus, the Odeon of Agrippa. It grew organically, shaped by benefactions and political decisions rather than a master plan.
Alexander and the Alexandrias
Alexander the Great founded dozens of cities across his conquests, planting Greek urban forms from Egypt to Bactria. Alexandria in Egypt, established in 331 BC and planned partly by Alexander's architect Deinokrates, became the paradigmatic Hellenistic city: a harbour city on a grid, with a main axial boulevard (the Canopic Way) flanked by colonnades, a royal quarter, a museum and library, and ethnic quarters for different communities. Little of Hellenistic Alexandria survives above ground — the modern city sits directly on top — but archaeological investigations beneath the streets and in the harbour have recovered traces of the ancient street grid and submerged architecture.
Antioch on the Orontes in Syria, founded by Seleucus I around 300 BC, followed a similar grid plan. Apamea, another Seleucid foundation, preserves one of the most spectacular main streets in the ancient world: a colonnaded avenue roughly two kilometres long with ruts worn deep into the limestone pavement by centuries of wheeled traffic. The city is currently inaccessible due to conflict, but the aerial photographs of its grid, extending across the Syrian plain, are among the most legible images of ancient urban planning.
The Roman Forum and Its Transformations
The Roman forum did not begin as a planned space. The Forum Romanum in Rome started as a low-lying area between hills, originally marshy and used for burials; it gradually accumulated temples, basilicas, and public buildings over centuries. By the late Republic it was hopelessly overcrowded, and Julius Caesar began the first of a series of Imperial fora — new, enclosed, formally planned civic spaces adjacent to the original.
Caesar's forum was completed by Augustus, who added his own Forum Augustum alongside it. Vespasian, Nerva, and Trajan each added another forum in turn. Trajan's Forum, the last and most grandiose, was designed by Apollodorus of Damascus and completed around 112 AD. Its centrepiece is Trajan's Column, still standing to its full height, but the complex originally included two libraries, a large basilica, colonnaded courtyards, and the enormous market complex known as Trajan's Markets — a multi-storey building carved into the Quirinal hill that functioned as both a commercial centre and administrative offices.
The Roman colony was a vehicle for exporting this urban model across the empire. When Rome founded a colonia, it typically assigned centuriated land outside the walls and laid out the city on a grid with two main arteries — the cardo (north-south) and the decumanus (east-west) — meeting at a central forum. Timgad in Algeria, founded under Trajan around 100 AD for legionary veterans, preserves this grid almost completely. The original planned square is still legible from above, though the city later sprawled beyond it. Timgad is a UNESCO World Heritage site.
Mesopotamian Cities and the Temple Economy
Mesopotamian cities had a different spatial logic from Greek and Roman ones. The dominant architectural form was the temple precinct, and the major cities — Ur, Nippur, Babylon, Nineveh — were organised around these sacred complexes. At Ur, the temenos (sacred enclosure) containing the ziggurat of Ur-Nammu occupied a substantial portion of the city's area. The ziggurat itself, a staged mud-brick tower dating to around 2100 BC and largely rebuilt under Nabonidus in the 6th century BC, was the most visible structure in the landscape.
Babylon under Nebuchadnezzar II in the 6th century BC was one of the most extensively planned cities of the ancient world. The Processional Way — a wide, paved road flanked by glazed brick walls decorated with lions — ran from the Ishtar Gate to the temple precinct of Marduk. The Ishtar Gate itself, reconstructed in the Pergamon Museum in Berlin from excavated fragments, gives an extraordinary impression of the planned ceremonial approach to a Mesopotamian city centre. The gate's blue-glazed brickwork with striding bulls and dragons was not decorative excess but an integral part of the urban experience.
Urban Planning in the Americas
Long before European contact, Mesoamerican civilisations developed sophisticated urban forms. Teotihuacan in central Mexico, occupied from roughly the 1st century BC to the 7th century AD and reaching a population of perhaps 100,000 at its height, was laid out on a grid oriented roughly 15 degrees east of north — an alignment that may have corresponded to astronomical observations. The Avenue of the Dead, the central spine of the city, ran for several kilometres past the Pyramid of the Sun, the Pyramid of the Moon, and numerous temple platforms. The city's apartment compounds, housing extended family groups, were arranged in standardised blocks across the grid.
Cahokia in present-day Illinois, the largest pre-Columbian city north of Mexico, occupied its site from roughly 900 to 1350 AD. Monks Mound, the central earthwork, rises roughly 30 metres and was once topped by a large building. The city was formally planned around a central plaza and aligned to the cardinal directions, with wooden palisades marking its core.
What Remains
Urban planning leaves durable evidence. Grids survive in the street plans of modern cities built on ancient foundations: Turin's street pattern still reflects the Roman colonia of Augusta Taurinorum; Chester's streets follow the axes of Deva, the legionary fortress. The decumanus and cardo of Timgad can be walked. The agora of Athens can be crossed on foot.
Open the map and explore the traces of ancient urban planning still visible in the landscape — the colonnaded streets, forum complexes, and surviving grid patterns that reveal how the ancients organised collective life.