by a number of settlements scattered across a moderately fer-
tile plain. Exchange among these settlements and Rome was
frequent and enshrined in the legal concept of commercium:
the right of any Latin or inhabitant of Latium to own Roman
land and to enter into a contract with a Roman. Every ninth
day in Rome was designated as a market day (nundina), and
these days were inscribed on the formal calendars listing the
annual festivals and events, which were found distributed
throughout central Italy. Other calendars simply indicate the
market days and their locations. Th e existence of these calen-
dars demonstrates the importance of regular local markets in
the economy of central Italy.
Agriculture was at the core of most of the commercial
activity in the ancient world, in terms of the short-range
movement of produce; long-range transhumance—or the
movement of animals, typically sheep, from summer upland
pastures to winter lowland pastures—and the exploitation of
animals as resources, especially in terms of meat and wool;
and the long-range movement of some staples, notably grain,
wine, and olive oil, across the Mediterranean. As the Roman
Empire grew, Rome became involved in existing trade pat-
terns and began to infl uence their development. To the east,
the long-established Greek cities and the Hellenistic empires
already boasted sophisticated networks of trade and ex-
change. To the west and north, key centers such as Marseilles,
in modern-day France, and Carthage, in modern-day Tunis,
were already present, but the Romans may have had a similar
impact on Spain, Gaul, and Britain in the fi rst century b.c.e.
as the Greeks and Phoenicians had on Rome in the eighth
century b.c.e., stimulating social and economic development.
One characteristic feature of this development was urbaniza-
tion, which altered economic relationships by creating cent-
ers of consumption that drew from hinterlands.
With regard to modes of transport, the sea was a crucial
conduit, and Rome expended signifi cant eff ort, most notably
through the campaigns of Pompey in 67 b.c.e., to clear the sea
of pirates. Th e physical evidence for maritime trade consists
most notably of shipwrecks, which give important informa-
tion about cargoes. Also, Rome constructed roads to facili-
tate the movement of armies and of goods across the empire,
sometimes utilizing preexisting structures and at other times
applying their engineering skills to construct new roads, such
as in Britain.
In time, Rome became the greatest center of consump-
tion of all. Rome’s population rose to a million by the end of
the fi rst century b.c.e., and a substantial number expected a
stable supply of food, some of which was provided by the state
and subsequently by the emperor. Th e demand for food was
increasingly satisfi ed by the Roman provinces; huge grain
ships plied the route from Egypt to Rome, and at Ostia and
Portus (fi rst created by Claudius in 46 c.e., with substantial
redevelopment by Trajan in 103 c.e.) new facilities were con-
structed to cope with disembarkation, storage, and distribu-
tion. Another physical sign of the relatively enormous level
of consumption in Rome is Monte Testaccio, a hill close tothe Tiber some 160 feet high, entirely composed of broken oil
amphorae, or containers. (Unlike wine amphorae, oil ampho-
rae could not be reused.) Most of these amphorae came from
the province of Baetica, in southwestern Spain, in the second
and third centuries c.e., and the hill comprises more than
50 million amphorae, in which over 1.5 billion gallons of oil
were imported into the city.
Other items in demand included building materials and
metals. Quarrying was a major enterprise, and like many
such enterprises was increasingly an imperial monopoly. At
Mons Claudianus, in Egypt, marble was quarried for use in
imperial palaces from Rome to Split, in modern-day Croatia.
In addition to the masses of workers, the quarrying required
an entire support network, such as to provide security over
the transport route. Once imperial authority broke down at
the end of the empire, quarrying ceased. Th e level of extrac-
tion of metal resources achieved during the empire was not
matched again until the Industrial Age; the opencast Roman
gold mine at Las Médulas, in Spain, was about 1.8 miles in
diameter, and lead and copper pollution from the Imperial
Period is detectable in the Greenland ice cap.
Metal was in demand, largely for coinage. Aft er the intro-
duction of coinage in Rome around 300 b.c.e. money became
the dominant means of exchange with respect to taxation,
wages, rent, and credit, although agricultural products also
remained signifi cant. Coinage was important at every level
of the economy and grew increasingly centralized, with lo-
cal mints disappearing and local currencies being phased
out in favor of a central Roman currency. Th at currency was
therefore vulnerable to debasement and consequent infl ation,
which became a problem in the third century c.e.
One commodity without which much of the rest of trad-
ing activity would have been impossible was human beings.
Slaves were bought and sold across the empire—the Greek
island of Delos had a notable slave market—and they contrib-
uted enormously through their labor to the productivity of
the empire. A ratio of one slave to every three free persons
has been suggested for Italy during this era. Owing to the Ro-
man custom of freeing slaves, some could achieve substantial
commercial standing themselves; this phenomenon is vividly
portrayed in Petronius’s fi ctional account, from the fi rst cen-
tury c.e., of the freedman Trimalchio, who was a substantial
landowner, had diverse trading interests, and lent money to
others, on the basis of which he sustained a comically exces-
sive lifestyle. Roughly contemporary documents from Puteoli
depict a family descended from a slave who for three genera-
tions engaged in loans and banking in a wide variety of enter-
prises, including ones run by other freedmen.
Regarding the overall nature of the Roman economy,
scholars have long debated the extent of the impact of trade
on the society and economy of the Roman Empire. In gen-
eral, wealth derived from land carried more positive over-
tones than wealth derived from commerce. Some senators
were engaged in trade, and a substantial wealthy elite across
the empire had a diversity of commercial interests. In relation1106 trade and exchange: Rome0895-1194_Soc&Culturev4(s-z).i1106 1106 10/10/07 2:31:06 PM