[T]here really is... a natural justice and injustice that is binding
on all men, even on those who have no association or covenant
with each other.
—Aristotle In Greek mythology, Chaos was the fi rst of the gods. We have Hesiod’s
weighty authority for this, but, in the context of international aff airs, we
could have guessed it in any event. In the luxuriant pantheons of ancient
peoples, we search in vain for a god or goddess of international law. Th ere is
no shortage of deities who are devoted to justice, either in a general sense or
in specialized areas, such as oaths or contracts. But there was a conspicuous,
and apparently universal, absence of gods or goddesses who were guardians
of justice between in de pen dent nations. If that gap was to be fi lled, then the
peoples of the world were going to have to do it— somehow or other— by
themselves.
It therefore appears all the more striking that glimmers of international
law can be discerned nearly as far back as historical rec ords will take us. Th e
international law in question was, to be sure, threadbare in the extreme by
our more demanding later standards. It was an assemblage of practices and
not an expression of any set of deep- seated general principles. In par tic u lar,
three areas of state practice were especially prominent. First was treaty mak-
ing. Th ere was a very general concern and expectation that treaties, once
solemnly concluded, must be scrupulously adhered to. Second was diplo-
matic relations— especially the according of certain privileges and immuni-
ties to envoys dispatched on offi cial missions from foreign powers. Th ird was
warfare. Th ere was a general, if somewhat vague, belief that wars should be
undertaken only if there is a just cause for them. And in certain contexts at
least, there were sometimes rules— or at least expectations— that certain
restraints on violence would be observed.
Not until later— and in its fullest form, much later— was there any con-
ception of a systematic body of principles covering all aspects of interna-
tional relations. Only when that occurred did it become possible to apply
international law to new and unforeseen situations. Th e fi rst moves in this
direction were taken in ancient China, in the pre imperial period. But the
decisive step came from the Mediterranean world, where the civilizations of