In this age when we think of weapons, we tend to think of aircraft, electronic guidance systems, bombs and missiles. Sophisticated star wars systems may come to mind or huge warships and aircraft carriers or even chemical or nuclear weapons.
Of course that has not always been the case.

An in depth study into the possible causes of the collapse of the Tang Dynasty in Ancient China. Includes comparison with the collapse of the Han Dynasty and a feature on how contemporary societies can learn from their mistakes.