Who said "Knowledge of oneself is the beginning of all power."?

This quote is attributed to Leonidas I.

Knowledge of oneself is the beginning of all power. - Leonidas I

"Knowledge of oneself is the beginning of all power."

Leonidas I Knowledge

King Warrior Ancient Greece 540–480

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"Spartans! Tonight we dine in hell!"

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"We're not just after treasure. We're preserving history."

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