In 1965, James Stockdale’s A-4E Skyhawk was shot down over Vietnam. He later remembered the moment like this: “After ejection I had about thirty seconds to make my last statement in freedom before I landed…And so help me, I whispered to myself: ‘Five years down there, at least. I’m leaving the world of technology and entering the world of Epictetus.’”

Stockdale spent more than seven years in a Vietnamese prison, and he wrote that Stoicism saved his life. Stockdale had spent years studying Stoic thought before deploying, and he drew on those teachings to endure his captivity. These words from Epictetus kept coming back to him: “Do you not know that life is a soldier’s service?…If you neglect your responsibilities when some severe order is laid upon you, do you not understand to what a pitiful state you bring the army?” While some of his fellow POWs tormented themselves with false hopes of an early release, Stockdale’s Stoic practice helped him confront the grim reality of his situation, without giving in to despair and depression.

Stockdale was not alone as a military man who drew strength from Stoicism. In her book The Stoic Warrior, Nancy Sherman, who taught philosophy at the Naval Academy, argued that Stoicism is a driving force behind the military mindset–especially in its emphasis on endurance, self-control, and inner strength. As Sherman writes, whenever her philosophy class at Annapolis turned to the Stoic thinkers, “many officers and students alike felt they had come home.”

For four more reasons why stoicism matters today, check out the rest of the article.