War should be made with no other view than the attainment of peace.

[Bellum autem ita suscipiatur, ut nihil aliud nisi pax quaesita videatur.]

Marcus Tullius Cicero (106-43 BC) Roman orator, statesman, philosopher
De Officiis [On Duties; On Moral Duty; The Offices], Book 1, ch. 23 (1.23) / sec. 80 (44 BC) [tr. McCartney (1798)]
    (Source)

(Source (Latin)). Alternate translations:

And as for war, it should never be undertaken with any other aim, but only that of obtaining an honourable peace.
[tr. Cockman (1699)]

Now in engaging in war we ought to make it appear that we have no other view but peace.
[tr. Edmonds (1865)]

But war should be undertaken in such a way that it may seem nothing else than a quest of peace.
[tr. Peabody (1883)]

We should only take up arms when it is evident that peace is the one object we pursue.
[tr. Gardiner (1899)]

We should so enter upon war as to show that our only desire is peace.
[ed. Harbottle (1906)]

War, however, should be undertaken in such a way as to make it evident that it has no other object than to secure peace.
[tr. Miller (1913)]

You should start a war, moreover, in such a way that you clearly have no other object than peace.
[tr. Edinger (1974)]