Pax by Tom Holland

"The mines, the roads, the harbours, the vineyards, the estates anything that sustained the Roman peace, depended on the protection of the legions, and without it would be lost." - Pax by Tom Holland. 

Can't help but read that and think the same thig applies to the US military and the US and world economies today. The importance of a strong military. 

"People sleep peaceable in their beds at night only because rough men stand ready to do violence on their behalf." - George Orwell