Born in 4 BC, Seneca was a Stoic philosopher in ancient Rome. In his lifetime he was a philosopher, statesman, beloved dramatist, early investment banker, and adviser to an insane emperor named Nero who eventually forced Seneca to take his own life. It is said that upon being forced to take his own life, Seneca did so with the utmost poise and tranquility, proving that his lifelong practice of Stoicism was deeply authentic. Today, Seneca is one of the most well-known, highly regarded, and widely read Stoics.
This pithy aphorism on suffering is a poignant reminder not to take your own mind too seriously: often, ruminating on our suffering compounds it. Thinking is beautiful, but thoughts can so easily create catastrophes out of nothing—read the Wikipedia page for "cognitive distortion" sometime. This memento is a reminder to take a step back when you're suffering and ask yourself: How bad is it, really? How much of this is nothing more than a giant castle of neurotic thoughts, an anxious thought-train to nowhere? If you catch yourself suffering due to your imagination, take a deep breath, practice presence for a few moments, acknowledge ambiguity, distract yourself if need be, and move on.