This document provides an overview of key characteristics that define cities according to experts. It discusses how cities are dense population centers that create social hierarchies and specialization of labor. Cities exist within networks and rely on surrounding agricultural regions for resources. They also have physical or legal boundaries and are characterized by monumental architecture and public buildings that establish a shared identity for citizens.

1. Spiro Kostof, "What is a City?" in The City Shaped: Urban Patterns and Meanings Through
History (Boston, 1991): 37-41
To conclude these introductory remarks, I think we can agree on some simple premises about
cities, regardless of their origin, their birthplace, their form, their makers. Two sensible
definitions, both from 1938, would allow us a good starting point. For L. Wirth, a city is "a
relatively large, dense, and permanent settlement of socially heterogenous [sic]
individuals." For Mumford, a city is a "point or maximum concentration for the power and
culture of a community." Here is my gloss on these fundamental premises.
A. Cities are places where a certain energized crowding of people takes place. This has nothing
to do with absolute size or with absolute numbers: it has to do with settlement density. The
vast majority of towns in the pre-industrial world were small: a population of 2,000 or less was
not uncommon, and one of 10,000 would be noteworthy. Of the almost 3,000 towns in the Holy
Roman Empire only about 12 to 15 (Cologne and Luebeck among them) had over 10,000
inhabitants.
A few statistics will serve as future points of reference. There were only a handful of genuine
metropolises in antiquity, among them imperial Rome in the 2nd century AD and Shanghai in
the 8th. In the Middle Ages this prodigious size is matched by Constantinople, Cordoba and
Palermo, the last two of which may have been in the 500,000 range in the 13th-14th
centuries. Baghdad may have had as many as 1,000,000 inhabitants before it was destroyed by
the Mongols in 1258. Again, we have Chinese parallels for such phenomenal concentrations as
Nanjing in the 15th century, and, in the late imperial era, Beijing, Suzhou and Canton. Beijing
remained the world's largest city until 1800, with a population of 2,000,000-3,000,000, when it
was overtaken by London. Its only close rivals in the I7th century were Istanbul, Agra, and
Delhi. Behind every enormous city of this sort, at least in the pre-industrial era, there lies a
vast, centralized state. Without its ruler, the city is bound to wither or collapse.
B. Cities come in clusters. A town never exists unaccompanied by other towns. It is therefore
inevitably locked in an urban system, an urban hierarchy. Even the lowliest of townlets has its
dependent villages. As Braudel puts it, "The town only exists as a town in relation to a form of
life lower than its own . . . It has to dominate an empire, however tiny, in order to exist." In
China, the urban hierarchy was expressed by suffixes added to the names of towns, like fu for
a town of the first order, chu for one lower down, and hieu for one lower still. Similarly, there
was a clearly defined urban hierarchy in Ottoman Anatolia of the 16th century headed by
Istanbul, and descending through a number of regional centers of about 20,000 to 40,000
inhabitants each to two sets of lower-order towns of under 10,000 and under 5,000.
C. Cities are places that have some physical circumscription, whether material or symbolic, to
separate those who belong in the urban order from those who do not. "Une ville sans mur n'est
pas une ville" (a city without walls is not a city), J.-F. Sobry wrote in his De l'architecture of
1776. Even without any physical circumscription, there is a legal perimeter within which
restrictions and privileges apply.

2. D. Cities are places where there is a specialized differentiation of work where people are priests
or craftsmen or soldiers and where wealth is not equally distributed among the citizens. These
distinctions create social hierarchies: the rich are more powerful than the poor; the priest is
more important than the artisan. Social heterogeneity is also axiomatic. The urban population
contains different ethnic groups, races, religions. Even in ethnically homogeneous cities, as the
original Yoruba cities were intended to be, there might be slaves or transient readers.
E. Cities are places favored by a source of income, trade, intensive agriculture and the
possibility of surplus food, a physical resource like a metal or a spring (Bath), a geomorphic
resource like a natural harbor, or a human resource like a king.
F. Cities are places that must rely on written records. It is through writing that they will tally
their goods, put down the laws that will govern the community, and establish title to property
which is extremely important, because in the final analysis a city rests on a construct of
ownership.
G. Cities are places that are intimately engaged with their countryside, that have a territory
that feeds them and which they protect and provide services for. The separation of town and
country, as we shall see repeatedly in this book, is thoroughly injudicious. Roman towns do
not exist apart from the centuriated land roundabout; great Italian communes like Florence
and Siena could not exist without their contado; and the same is true of New England towns
and their fields and commons. Polis, civitas, commune, township -- all these are terms that
apply to an urban settlement and its region.
Often the city-form is locked into rural systems of land division. The Romans commonly
correlated the main north-south and east-west coordinates of the centuriation, the division of
rural land into squares that were supposed to be the theoretical equivalent of one hundred
small holdings, with the cross-axes of the city. The National Survey that regulated two-thirds
of the United States territory determined the placement and size of many towns. It is,
furthermore, of great interest to us that pre-existing rural property bounds will often influence
subsequent urban lines and determine the shape of urban development.
The question of which came first, town or country, is not simple. The first towns in the Middle
East or China controlled and organized an already functioning countryside. In the opening of
the American West, the towns preceded the farms and made their operations possible. By the
same token, the strains of a deeply felt disagreement about the relative superiority of town and
country can be heard throughout history. Two examples, as distant as I can make them. In
China, the Confucian view that the proper function of the elite was to govern, that government
presumed cities, and that the purpose of government was to civilize the countryside, clashes
with the ultimately Taoist and Buddhist ideal of rural existence. Thomas Jefferson's agrarian
republicanism had no use for cities in the structure of the young nation. Cities were "sores on
the body politic."
H. Cities are places distinguished by some kind of monumental definition, that is, where the
fabric is more than a blanket of residences. This means a set of public buildings that give the
city scale, and the citizenry landmarks of a common identity. Technological monuments are

3. also important: Rome had its aqueducts; Tikal, a large manmade reservoir; Anuradhapura in
Sri Lanka, a hydraulic system of monumental proportions. In the public realm early cities
under central authority chose to emphasize the palace and the temple. In the people's city, the
princely palace disappears, or is translated into a palace of the people, and the temple is
"secularized." That is the case of the Greek polis, and that too is the case of the European
commune in the Middle Ages with its palazzo pubblico or Rathaus and its "civic" cathedral.
I. Finally, cities are places made up of buildings and people. I agree with Kevin Lynch: "City
forms, their actual function, and the ideas and values that people attach to them make up a
single phenomenon." Hundreds of new towns in every age of history were still-born, or died
young. The majority of the grids laid out by railroad companies along their lines in the 19th
century never fleshed out into real towns. Conversely, we can discount scholarly claims for the
fully established and long-lived Mayan sites or for places like Angkor Thom and Nakhon
Pathom that they were not real cities because they had no resident population. These
spectacular ceremonial settings and the priests and the builders and the artisans and the people
selling them things belonged together. We will be well served, in reading this book to recognize
that there have been cityless societies, and times when cities were vestigial marks in a
predominantly rural landscape. Let us recognize, too, that the urban and pastoral ways of life
were at times contending social systems; and further, that the history of human settlement must
be predicated on a rural-urban continuum, and that the city as a self-contained unit of analysis
must be seen as conditional enterprise. For all that, the city is one of the most remarkable, one
of the most enduring of human artifacts and human institutions. Its fascination is inevitable:
its study is both duty and homage.
Ours is certainly not a story restricted to the past. At this very moment cities are being born ab
ovo, either through the legal instrument of incorporation, or through parthenogenesis. Since
1950 more than 30 new towns were created in England. In France, along two preferential axes
following the Seine Valley, several new towns for 300,000 to 500,000 each are in the process of
building -- St.-Quentin-en-Yvelines, Evry, Marne-la-Valle. Others have been started outside
the Paris region. In the Soviet Union we have many hundreds of recent new towns, closely
associated with the spread of industrialization. In the United States, the "new communities"
program introduced in the Sixties has had its own considerable offspring.
It is a long haul, from Jericho to Marne-la-Valle. My ambition to encompass all of urban
history through this thematic approach rests on a paradox. Cities in their physical aspect are
stubbornly long-lived. As Vance put it, "the most enduring feature of the city is its physical
build, which remains with remarkable persistence, gaining increments that are responsive to
the most recent economic demand and reflective of the latest stylistic vogue, but conserving
evidence of past urban culture for present and future generations." At the same time "urban
society changes more than any other human grouping, economic innovation comes usually most
rapidly and boldly in cities, immigration aims first at the urban core forcing upon cities the
critical role of acculturating refugees from many countrysides, and the winds of intellectual
advance blow strong in cities. . ."