From www.mountvernon.org: "At the end of the hard winter at Valley Forge, General George Washington defied a congressional ban on theatrical productions and entertained his men with a production of Joseph Addison's 1713 tragedy Cato."
See also George Washington's Favorite Play
From Classical Wisdom Weekly: "The founding fathers were also inspired by the philosophy. George Washington was introduced to Stoicism by his neighbors at age seventeen, and afterwards, put on a play about Cato to inspire his men in that dark winter at Valley Forge. Whereas Thomas Jefferson had a copy of Seneca on his nightstand when he died."
Jefferson's reading list includes Epictetus, Seneca & Marcus Aurelius