 A study based on personal letters from soldiers of the 18th-century Prussian Army concludes that combatants may have had PTSD.Aspects of PTSD in soldiers of ancient Assyria have been identified using written sources from 1300–600 BCE.These Assyrian soldiers would undergo a three-year rotation of combat before being allowed to return home, and were purported to have faced immense challenges in reconciling their past actions in war with their civilian lives.