9.3 Customary Law
9.3.1 Diplomacy was conducted by envoys rather than by resi-
dential ambassadors. Envoys enjoyed immunity in the sense of invi-
olability of their person; there is no allusion to the modern doctrine
of immunity from liability for illegal acts. The envoy of a friendly
state was deemed a guest of the host monarch, to be treated in
accordance with the accepted norms of hospitality. Permission of the
host was required before the envoy could depart. Inordinate deten-
tion might lead to diplomatic protests but was, strictly speaking, legal.
Violation of an envoy’s person, on the other hand, was a casus belli.9.3.2 A state was responsible for crimes committed against foreign
nationals on its territory. The victims’ ruler would intervene on their
behalf with the ruler of the state deemed responsible. The problem
arose mostly with regard to foreign merchants, who were vulnera-
ble to murder and robbery. The state was obliged to pay compen-
sation to the victims or their families if the culprits were not caught.
The modalities of compensation might be regulated by treaty, as
examples from Ugarit in the late second millennium show.9.3.3 Kings had a natural prerogative to grant asylum to fugitives.
They were under no legal obligation to return fugitives to the coun-
try from which they had fled, except under the express terms of a
treaty. For this reason, many treaties contain clauses regulating extra-
dition. Another exception may have been vassals, who would be
obliged (legally, not just politically) to return fugitives to their over-
lord under their general duty of loyalty. Hittite treaties, however,
make the vassal’s duty of extradition an express term.9.3.4 Nothing certain can be said about the rules of war. A dec-
laration of war sometimes preceded hostilities, but there appears to
have been no general obligation. Prisoners of war were at the mercy
of their captors, to treat at their discretion. They were either killed,
enslaved (often being blinded), or ransomed. Civilians were regarded
as legitimate booty. Humane treatment seems to have depended on
political expediency and internal inhibitions rather than on recog-
nized legal rules.86
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