On Episode 4 of "Legends & Lies: The Patriots" we saw General George Washington take command of the Continental Army. 

Washington struggled with the challenges of building a military force from an untested colonial militia and limited supplies.

On top of that in 1775, Washington was faced with a traitor in his ranks, discovering that Dr. Benjamin Church, part of his inner circle, was divulging secrets to the British.

It was a wake-up call for Washington as he realized that the British knew much more than he believed and that he needed a sophisticated intelligence network.

It would also not be the last time that Washington would be betrayed by a trusted general.

Meantime, the British commanders went to shows in Boston in which the rebels were mocked, but their illusions about Washington would soon be dispelled.

Watch the riveting scenes above, with appearances by executive producer Bill O'Reilly and Fox News' own Brian Kilmeade, author of "The Secret Six: The Spy Ring That Saved the American Revolution."

The second season of the hit docu-series Legends & Lies brings you the stories behind the American Revolution, as they really happened.

On next Sunday's episode, Thomas Jefferson: Independence Declared, you'll see how the nation's founders crafted our founding document as Washington battles the British in New York.

Tune in to "Legends & Lies: The Patriots" on Sundays at 8:00pm ET on Fox News Channel!

'Legends & Lies' Recap: The Boston Massacre and the Birth of the Revolution

Episode 2 Recap: The True Story of Paul Revere's Famous Ride

Episode 3 Recap: See the Powerful Re-Creation of the Battle of Bunker Hill