Humanities › History & Culture Who Said 'If You Want Peace, Prepare for War'? This Roman idea is still in many minds today Share Flipboard Email Print Charles Mann/ E+/ Getty Images History & Culture Ancient History and Culture Rome Figures & Events Ancient Languages Greece Egypt Asia Mythology & Religion American History African American History African History Asian History European History Genealogy Inventions Latin American History Medieval & Renaissance History Military History The 20th Century Women's History View More By N.S. Gill Ancient History and Latin Expert M.A., Linguistics, University of Minnesota B.A., Latin, University of Minnesota N.S. Gill is a Latinist, writer, and teacher of ancient history and Latin. She has been featured by NPR and National Geographic for her ancient history expertise. our editorial process N.S. Gill Updated July 05, 2019 The original Latin of the expression "if you want peace, prepare for war" comes from the book "Epitoma Rei Militaris," by the Roman general Vegetius (whose full name was Publius Flavius Vegetius Renatus). The Latin is, "Igitur qui desiderat pacem, praeparet bellum." Before the fall of the Roman Empire, the quality of its army had begun to deteriorate, according to Vegetius, and the decay of the army came from within itself. His theory was that the army grew weak from being idle during a long time of peace and stopped wearing its protective armor. This made them vulnerable to enemy weapons and to the temptation to flee from battle. Vegetius' quote has been interpreted to mean that the time to prepare for war is not when war is imminent but rather when times are peaceful. Likewise, a strong peacetime army could signal to would-be invaders or attackers that the battle may not be worth it. Vegetius' Role in Military Strategy Because it was written by a Roman military expert, Vegetius' "Epitoma Rei Militaris" is considered by many to be the foremost military treatise in Western civilization. Despite having little military experience of his own, Vegetius' writings were highly influential on European military tactics, particularly after the Middle Ages. Vegetius was what was known as a patrician in Roman society, meaning he was an aristocrat. Also known as the "Rei Militaris Instituta," Vegetius' book was written sometime between 384 and 389. He sought a return to the Roman military system of legion formation, which was highly organized and depended on a disciplined infantry. His writings had little influence on the military leaders of his own day, but there was a particular interest in Vegetius' work later, in Europe. According to "Encyclopedia Britannica," because he was the first Christian Roman to write about military affairs, Vegetius' work was, for centuries, considered the "military bible of Europe." It's said that George Washington had a copy of this treatise. Peace Through Strength Many military thinkers have modified Vegetius' ideas for a different time, such as to the shorter expression of "peace through strength." Roman Emperor Hadrian (76–138) was probably the first to use that expression. He has been quoted as saying "peace through strength or, failing that, peace through threat." In the United States, Theodore Roosevelt coined the phrase "Speak softly and carry a big stick." Later, Bernard Baruch, who advised Franklin D. Roosevelt during World War II, wrote a book titled "Peace Through Strength" about a defense plan. The phrase was publicized widely during the 1964 Republican presidential campaign and was used again during the 1970s to support the construction of the MX missile. The adage justified the Cold War buildup of nuclear missiles as a deterrent to war. Ronald Reagan brought "peace through strength" back into the limelight in 1980, accusing President Jimmy Carter of weakness on the international stage. Said Reagan: "We know that peace is the condition under which mankind was meant to flourish. Yet peace does not exist of its own will. It depends on us, on our courage to build it and guard it and pass it on to future generations."