Most powerful is he who has himself in his own power.

Seneca (c. 4 BCE–65 CE), the Stoic philosopher and Roman statesman, repeatedly contrasts outward power—office, wealth, influence—with the inward mastery prized by Stoicism. Writing in an era of imperial politics and personal peril (including his own rise under Nero and eventual forced suicide), Seneca urges readers to locate freedom and strength in self-command: governing passions, fears, and desires rather than being governed by them. The sentiment aligns with themes he develops across his moral essays and letters, where the truly “free” person is the one not enslaved by anger, ambition, or fortune, even when living under autocratic rule.

The line asserts a Stoic paradox: the greatest power is not domination over others but dominion over oneself. “Having oneself in one’s own power” means possessing inner sovereignty—reasoned control of impulses and emotional reactions—so that external events cannot compel moral compromise or mental turmoil. Seneca implies that political authority, physical force, or social status are fragile and contingent, while self-mastery is durable and genuinely empowering. The quote also reframes freedom as an ethical achievement: the person who can restrain anger, endure loss, and resist temptation is “most powerful” because they cannot be easily manipulated by threats, flattery, or fortune.