“Give me liberty or give me death!” Patrick Henry’s forceful declaration to the Second Virginia Convention in March 1775, proved a tipping point, convincing his fellow delegates—including George Washington and Thomas Jefferson—to vote in favor of committing Virginian troops to the looming revolutionary battle. Henry’s rhetoric echoed the writings of French philosopher Jean-Jacques Rousseau, who opened his influential 1762 work, The Social Contract, with the words “Man is born free and everywhere he is in chains.”

By the 1760s, the founding fathers and their peers eagerly devoured French political philosophy. “It became almost a patriotic duty for colonists to admire France as a counterpoise to an increasingly hostile England,” wrote historian Lawrence Kaplan of Kent State University. The British may have triumphed militarily over their French rivals in the global conflict known as the Seven Years’ War. But America’s future founders disparaged the way the British (in their eyes) trampled on their own constitution, turning instead to France for new ideas about freedom and independence.

Rousseau, for one, spoke of sovereignty residing not in a monarch, but in the people as a group, and of the need to craft laws for the general good. Thomas Jefferson’s rhetoric (including “All men are created equal”) owed much to Rousseau. However, the drafters of the U.S. Constitution may have been most inspired by the Baron de Montesquieu, who argued in his treatise The Spirit of the Laws that avoiding despotism required a government of checks and balances.

Without the ideas of these French philosophers to inspire them in tough times, it’s hard to imagine the revolution succeeding.

Still smarting from its defeat in the Seven Years’ War and loss of colonies worldwide, including much of Canada, France saw America’s rebellion as an opportunity for revenge—and to re-establish part of its own empire at British expense. The wily Comte de Vergennes, France’s foreign minister, urged Louis XVI to support the Americans, arguing that “providence had marked out this moment for the humiliation of England.”

French participation transformed what might otherwise have been a lopsided colonial rebellion into a significant war, with potential to become another global conflict. The British, it turned out, had little appetite for this—especially when other European powers such as Spain and the Dutch Republic proved willing to support the colonists. The geopolitical calculus made it difficult for British legislators to accept the prospect of a prolonged, costly and global battle.

One evening in December 1775, Benjamin Franklin, a delegate to the Second Continental Congress—and a member of its Committee of Secret Correspondence, which conducted foreign communications—slipped silently into Philadelphia’s Carpenters’ Hall along with four of his colleagues to commit what the British would certainly view as treason. They had come to meet Julien-Alexandre de Bonvouloir, a secret envoy from the French regime. The clandestine meeting sowed the seeds of a strong covert relationship between the revolutionaries and France that predated the formal 1778 treaties between the two.

Bonvouloir’s reports back to France were enthusiastic. “Everyone here is a soldier,” he said of the colonies. Franklin’s team of negotiators sent Silas Deane to Paris under the guise of a merchant looking for goods to buy for resale to Native Americans. Deane’s real quest was very different: He sought military engineers, along with clothing, arms and ammunition for 25,000 soldiers. Oh, and credit from the French to pay for it all. Within two weeks of arriving, he had what he wanted, and France had become a secret supporter of the revolution.

When Benjamin Franklin himself traveled to Paris in November 1776, much of the secrecy surrounding the negotiations with France fell away. But Franklin’s popularity with everyone from the aristocracy (he encouraged Lafayette to volunteer) to the general public put more pressure on the French regime to keep supporting their new allies—even amid reports of American losses and their dreadful winter at Valley Forge.

Great ideas can wither and die without the capital to support them. And from the earliest days, America’s uprising depended on French willingness to provide open-ended credit that enabled Deane and his partners to ship supplies to the beleaguered revolutionary forces. Ultimately, France provided about 1.3 billion livres of desperately-needed money and goods to support the rebels. Estimates suggest that at the colonists’ October 1777 victory at Saratoga, a turning point in the war, 90 percent of all American troops carried French arms, and they were completely dependent on French gunpowder.

That triumph prompted the French to open their coffers wider. Once the relationship was formalized in twin agreements early in 1778 (the Treaty of Alliance and the Treaty of Amity and Commerce), the flow of supplies soared, along with the numbers of soldiers and sailors crossing the Atlantic to fight for the American cause.

Roughly 12,000 French soldiers served the rebellion, along with some 22,000 naval personnel, aboard 63 warships. Lafayette was the one of the earliest—and most prominent —officers to join. The comte de Rochambeau, commander in chief of all French forces, played a crucial role in containing the English fleet and in the final campaigns. The comte de Grasse reinforced revolutionary forces in Virginia with French troops from Saint-Domingue (now Haiti) in the Caribbean, then dealt Britain’s navy a decisive defeat at the 1781 Battle of the Chesapeake. It would be an army led by Washington, Lafayette and Rochambeau together that struck the decisive blow at Yorktown.

Without France’s aid, American revolutionaries might have been seen by other major powers merely as treasonous subjects rebelling against their rulers. French willingness to negotiate with Deane, Franklin and their successors conferred legitimacy on American leaders. The Treaty of Amity and Commerce of 1778 formally acknowledged the United States as an independent nation and opened the way for Americans to continue trading internationally. Over time, France also enlisted the aid of other major European powers (Spain allied itself with the United States in 1779) while sidelining others, like Austria, which never joined the war but made clear it would back France in any wider conflict.

Following the Yorktown surrender, France’s diplomatic support (and yet another loan) proved critical in reaching a formal end to the conflict, with the 1783 Treaty of Paris. Both the French and the Americans refused British offers of separate peace agreements, and French foreign minister Vergennes took a key role in brokering the treaty. Ultimately, it wasn’t until Britain and France settled their differences that the Americans finally signed the Treaty of Paris.