must first of
all be exact in his attitude towards its past and present. International
law as the law of the international community of states, such as is the
present-day conception of it, is of comparatively modern origin. Science
dutifully traces it back to Hugo Grotius as its father. In his immortal
work on the _Law of War and of Peace_ he, with masterly touch, focalizes
(as it were) all the tendencies which asserted themselves during the
latter half of the middle ages into a law between independent states, in
such sort that all subsequent development goes back to him. Undoubtedly
the roots of this law reach back into the remotest past of civilization,
for independent states, nay, independent tribes too, cannot have more or
less frequent dealings with each other without developing definite forms
therefor. And so the immunity which must everywhere be conceded to
ambassadors and heralds will probably be the oldest root of
international law.

[Sidenote: No international law in antiquity.]

2. But all attempts to find in the ancient world a law of the same kind
as modern international law must inevitably come to grief on the fact
that the idea of a community of law between civilized states was
entirely foreign to antiquity, and only begins to make its gradual
appearance in the last third of the middle ages. The Jewish ideal of
perpetual peace and the union of all mankind under _One_ God, foreseen
in prophetic vision by Isaiah (ii. 2-4), may be taken as the first
formulation of pacificist doctrine, which of course implies a community
of law between all states, but the prophet does not apprehend this
community of law as an independent idea. This idea was likewise unknown
in its generality to Greek civilization, although certainly looming
before it with some clearness in the international relations of the
Greek city-states one to another. But even if we may speak of a law
resembling in many respects modern international law as prevailing
between the states of ancient Greece, this law must nevertheless be
limited to Greek states, foreign states and peoples standing outside
this community of law as barbarians. On the other hand, Roman law
possessed, it is true, a mass of legal rules for the intercourse between
the Roman Empire and all foreign states, but these rules were _Roman_
law and not rules of an international law such as postulates an
international community of law.

[Sidenote: How the conception of a family of