8 Chapter One
canal, fortifying a city, or erecting a temple. This basic transfer of
resources from the many to a few was supplemented by a circulation
of luxury goods among members of the ruling elites—partly gift-
giving from the great to followers and subordinates, partly tribute
from subordinates to the great. Trade across political frontiers was
really a variation within this larger pattern of exchanges among men of
power. It differed from such exchanges in being more easily inter
rupted, and less strongly colored by patterns of deference and conde
scension of the kind that prevailed within the ruling elites of civilized
states.^8
Another feature of ancient empires deserves emphasis, to wit, the
fact that there was an optimal size for such polities. The smooth func
tioning of a tax-collecting administration required the king to reside
for at least part of each year in a capital city. Information needed for
meting out reward and punishment to key servants of the crown could
best be concentrated in a single locality. Such matters had to be at
tended to promptly, or else the administrative machine would quickly
run down and cease to be capable of concentrating resources at any
thing like maximal capacity. It was equally vital to maintain a body
guard around the person of the ruler, sufficient to overawe or defeat
any likely rival who might meditate revolt. This, too, was best
achieved by residing much of the time in some central location where
natural routes of transport, especially waterways, made it feasible to
gather necessary stores of food year in and year out from the sur
rounding countryside.
But if a capital city was essential, and if residence by the ruler for
part or all of the year in the capital was likewise essential, then a limit
was automatically imposed on the extension of imperial frontiers. To
exert sovereign power effectively, a ruler had to be able to bring
superior force to bear if forcibly challenged either by revolt from within
or by attack from without. But if the ruler and his bodyguard had to
reside at least part of the year in a capital city, then a march of more
than about ninety days from the capital became risky.
When he invaded Greece, Xerxes trespassed far beyond the
- In the Far East, however, in the first century B.C. the Chinese empire established a
pattern of “tribute trade” with neighboring rulers. Ritual deference was central in this
relationship; indeed the Chinese authorities paid dearly in tangible commodities for the
ceremonial acknowledgment of their superiority. Yet in another sense the Hsiung-nu
and other border folk, in submitting differentially to the Chinese court rituals, opened
themselves to Sinification, paying thereby a high, if intangible, price. Cf. the interesting
analysis of this relationship in Yu Ying-shih, Trade and Expansion in Han China: A
Study in the Structure of Sino-Barbarian Economic Relations (Berkeley and Los Angeles,
1967).
