“Happy the state which in times of peace is yet prepared for war.”
Felix est illa civitas quae in pace bellum cogitat.
Gerald of Wales (1146) Medieval clergyman and historian
Book 2, chapter 9, p. 271.
Compare Vegetius De Re Militari: "Qui desiderat pacem, praeparet bellum" (Let him who desires peace prepare for war).
Descriptio Cambriae (The Description of Wales) (1194)