At the outset of the Revolution, the Americans realized their limitations. All the resources seemed to lie across the ocean. Benjamin Franklin was dispatched to France to foster financial support as well as troops. Remember that King George III had already bought support with Hessian mercenaries from Germany.
Franklin's diplomatic prowess certainly succeeded, but the victories, especially at Saratoga, spoke volumes. After seeing proof that the Continental army was a capable fighting force, and upon hearing rumors that Britain might offer America territorial concessions to reach peace, the French government ministers had enough confidence in General Washington to recommend to King Louis XVI that he sign a treaty of alliance with the Americans. In February 1778, this alliance was made formal, with France diplomatically recognizing “the United States of America.” Soon after the signing, Spain, which had offered to remain neutral if Britain returned Gibraltar, threw in support since its demands were not met. Spain and France were already allies as well.
French aid was certainly welcome, but French egos were not. Many of the officers who arrived in the summer of 1777 demanded exalted rank and commensurate pay for their limited military experience. An exception was the young Marquis de Lafayette, who arrived in Philadelphia volunteering to serve on America's behalf at his own expense. This quickly won Washington's praise and the admiration of American troops. Lafayette had been rushed into battle at Brandywine, and by December he had his own command and commission as a major general. In 1779, Lafayette returned to his native country to continue lobbying for further aid, thus proving to be a valuable liaison between the Continental army and the French government.