Epictetus believed that the key to transforming oneself into a wise person was learn what was?

You're absolutely right! Epictetus, the Stoic philosopher, believed that the key to becoming wise was understanding what is within our control and what is not.

He famously said, "Some things are in our control and others not." This simple statement encapsulates his entire philosophy.

Here's how his understanding of control relates to wisdom:

* What we control: Our thoughts, emotions, judgments, and reactions. We can choose how we respond to external events.

* What we don't control: External events, other people's actions, the weather, our physical appearance, etc. We can't change these things directly.

Epictetus believed that focusing on what we can control (our internal world) is essential for happiness and wisdom.

By accepting that we can't control external circumstances, we can free ourselves from unnecessary worry and frustration. Instead, we can focus on developing our internal strength, virtue, and resilience.

In summary, Epictetus' belief was that by accepting the reality of what we can and cannot control, we can cultivate wisdom and find inner peace.