De Re Militari

Don’t Wage War without It

Before Sun Tzu’s ‘The Art of War’ reached the West, the leading book on how to wage war was a book called ‘Concerning Military Affairs’ by Flavius Vegetius Renatus. This was also known by its Latin name ‘De Re Militari.’

History of the Book

Renatus wrote this book to advise Emperor Valentinian II and encourage him to reform the army to its ancient splendor.

We don’t know a lot about Flavius Vegetius Renatus. He seems to be a high-ranking Roman from the 4th century AD, but that’s all the biography we have of him.

Well, he did admit that he got most of his information from Cato the Elder, Cornelius Celsus, Paternus, and Frontinus, plus what he could glean from the rules of Augustus, Trajan, and Hadrian. In other words, he didn’t do a lot of soldiering himself.

This book wasn’t popular with the Romans, but copies became widespread by the 10th century, and it was translated into English, French, and Bulgarian before the 1400’s. It was the handbook of the Crusaders and frequently referenced, though the military men of the time only seemed interested in the third book, the one of tactics.

Contents of the Book

First, Renatus fawns on Valentinian, and then he jumps into how Romans have to return to the military tactics of their forbears.

Then you are off to the races with a description of picking, training, and disciplining recruits. He is big on recruiting tall men from the countryside (all those city-slickers are too soft) and starting with very young boys.

He also doesn’t want anyone to join the army that come from soft, womanly jobs like fishing. His example, not mine.

He then presents detailed descriptions of how to set up a military camp.

Book Two also starts by flattering the emperor, but then moves to how the army is to be organized. A lot of familiar infantry organization is here. Stuff about keeping records and forming cohorts.

Book Three is about provisioning, using spies, going on marches, managing troops, and going on campaigns. He describes marching near an enemy and fortifying your encampment near the enemy. You can see why the likes of Richard the Lionheart might have been partial to the third book.

He ends his third book with general maxims about arranging attacks.

Conclusions

Man, there is nothing like the advice of the armchair expert. We are so smart, Renatus and I.

I don’t know how reasonable Renatus’s ideas are, but I think there was a reason the Romans didn’t adopt it and medieval warlords were selective about its use. It doesn’t take calvary into account, and the recruiting section probably is to be taken with a grain of salt is what I guess.

All that said, it was used until the 1900’s and highly praised. I guess the reminder to keep troops well-fed and in good spirits never wanes in usefulness.

Unlike one of Albertus Magnus’s beasts, it is a short book, and relatively easy to find for cheap-ish. I bought mine online. It is worth a read to anyone interested in what at least people thought the Romans should have done.