Happy is the man who can endure the highest and lowest fortune. He who has endured such vicissitudes with equanimity has deprived misfortune of its power.

The saying condenses a central Stoic claim associated with Seneca: happiness depends less on external circumstances than on the steadiness of one’s judgment. “Highest and lowest fortune” points to the full swing of life’s reversals—prosperity and loss, honor and disgrace, health and illness. To “endure” them with equanimity is not passive resignation but trained inner freedom: the person who has learned not to stake their well-being on what Fortune can give or take has, in effect, stripped misfortune of its sting. The quote thus praises resilience grounded in virtue and rational self-command, rather than in luck or comfort.