der--the general security in its lowest terms--comes to be
secured more effectively by regulation and ultimate putting down of
the feud as a remedy, payment of composition becomes a duty rather
than a privilege, or in the case of injuries by persons or things in
one's power a duty alternative to a duty of surrendering the offending
child or animal. The next step is to measure the composition not in
terms of the vengeance to be bought off but in terms of the injury. A
final step is to put it in terms of reparation. These steps are taken
haltingly and merge into one another, so that we may hear of a
"penalty of reparation." But the result is to turn composition for
vengeance into reparation for injury. Thus recovery of a sum of money
by way of penalty for a delict is the historical starting point of
liability.

One's neighbor whom one had injured or who had been injured by those
whom one harbored was not the only personality that might desire
vengeance in a primitive society. One might affront the gods, and by
one's impiety in so doing might imperil the general security, since
the angered gods were not unlikely to hit out indiscriminately and to
cast pestilence or hurl lightning upon just and unjust alike in the
community which harbored the impious wrongdoer. Hence if, in making a
promise, one called the gods to witness it was needful that
politically organized society, taking over a field of social control
exercised by the priesthood, give a legal remedy to the promisee lest
he invoke the aid of the gods and jeopardize the general security.
Again in making a promise one might call the people or the
neighborhood to witness and might affront them by calling them to
witness in vain. Here, too, the peace was threatened and politically
organized society might give a remedy to the promisee, lest he invoke
the help of his fellow citizens or his neighbors. A common case might
be one where a composition was promised in this way for an injury not
included in the detailed tariff of compositions that is the staple of
ancient "codes." Another common case was where one who held another's
property for some temporary purpose promised to return it. Such a case
is lending; for before the days of coined money, the difference
between lending a horse to go to the next town and lending ten sheep
to enable the borrower to pay a composition is not perceptible. Thus
another starting point of liability is recovery of a thing certain, or
what was