“An adversary is more hurt by desertion than by slaughter. (General Maxims)”
De Re Militari (also Epitoma Rei Militaris), Book III, "Dispositions for Action"
Original
aduersarium amplius frangunt transfugae quam perempti.
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Publius Flavius Vegetius Renatus 16
writer of the Later Roman EmpireRelated quotes

“A general is not easily overcome who can form a true judgment of his own and the enemy's forces. Valour is superior to numbers. The nature of the ground is often of more consequence than courage. (General Maxims)”
Amplius iuuat uirtus quam multitudo.
De Re Militari (also Epitoma Rei Militaris), Book III, "Dispositions for Action"

“To ravage, to slaughter, to usurp under false titles, they call empire; and where they make a desert, they call it peace.”
Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.
Close of chapter 30 http://la.wikisource.org/wiki/De_vita_et_moribus_Iulii_Agricolae_%28Agricola%29#XXX, Oxford Revised Translation
Variant translations:
They plunder, they slaughter, and they steal: this they falsely name Empire, and where they make a wasteland, they call it peace.
Loeb Classical Library edition
To plunder, butcher, steal, these things they misname empire: they make a desolation and they call it peace.
As translated by William Peterson
More colloquially: They rob, kill and plunder all under the deceiving name of Roman Rule. They make a desert and call it peace.
This is a speech by the Caledonian chieftain Calgacus addressing assembled warriors about Rome's insatiable appetite for conquest and plunder. The chieftain's sentiment can be contrasted to "peace given to the world" which was frequently inscribed on Roman medals. The last part solitudinem faciunt, pacem appellant (they make a desert, and call it peace) is often quoted alone. Lord Byron for instance uses the phrase (in English) as follows,
Agricola (98)
“To ravage, to slaughter, to usurp under false titles, they call empire; and where they make a desert, they call it peace.”
Auferre, trucidare, rapere, falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.
Attributed by Tacitus in Agricola (c. 98)
Oxford Revised Translation (at Project Gutenberg) http://la.wikisource.org/wiki/De_vita_et_moribus_Iulii_Agricolae_%28Agricola%29#XXX
Translation: They plunder, they slaughter, and they steal: this they falsely name Empire, and where they make a wasteland, they call it peace. — translation Loeb Classical Library edition
Translation: To plunder, butcher, steal, these things they misname empire: they make a desolation and they call it peace. — translation by William Peterson

“Nothing is so useless as a general maxim.”
On Machiavelli (1827)


“Sometimes, questions are more hurtful than insults.”
The First Phone Call from Heaven