In 1775, the Continental Congress considered whether or not to declare independence
so as to achieve the liberty and opportunity they were denied as British colonies.
Such a declaration would be considered a revolt, for which the punishment was hanging,
and the chances for military success were very slight, since the American colonies
had little money, no arms industry, and only about one-third the population of Great Britain.
A secret committee led by Ben Franklin explored the prospect of getting aid from France, which had three times the population of Great Britain, extensive military and trading resources, and an interest in turning British attention away from North America.
France almost immediately sent armaments and experienced senior officers to aid the United States, and after a year of fighting that showed the commitment and strength of U.S. support for independence France signed a trade and military treaty recognizing the United States as an independent nation and exchanged ambassadors with the United States .
France sent two expeditionary forces to fight in the United States, with dozens of ships and thousands of troops. French forces sustained several thousand deaths and lost of many ships in U.S. waters, and even greater losses in fighting around the globe.
France also gave and loaned to the United States millions of silver livres. Both U.S. merchants and foreign governments valued this "hard cash" much more highly than the United States' paper Continental dollars.
An Elegant Summary of the MarchThe National Park Service site for the Washington-Rochambeau Revolutionary Route National Historic Trail has a 14-page historical summary with historic maps.
See NPS summary
This provides an elegant over-view of the march and might be read before reading the more detailed pages noted in the left-side page-links.
Those colonists who sought independence understood that achieving it
was a task beyond the resources then developed in the area of the colonies,
so they sent representatives to many nations seeking military, financial, and diplomatic assistance.
Some of these nations refused any assistance, some fended off the representatives completely, some provided some foreign trade, some made loans that posed less risk of retaliation rom Great Britain than would recognition of the independence of the U.S.
Some European nations that we recognize today were not nations in 1775. For example, the area that is now Germany was then a patchwork of city-states and duchies whose trading and political relations were somewhat coordinated by an assembly that met infrequently. This collective was known as the Holy Roman Empire and was the remnant of a much larger and more tightly-governed empire that collapsed at the start of the Dark Ages.
The Amerindian nations have often been forgotten in the rush of history, but in 1775 they were powerful forces that could and did threaten and damage large areas of the colonies, often rightly provoked by colonial expansionism and land grabs. In all of the intercontinental struggles for control of the North American continent Amerindian support was courted by both sides, and the Amerindians suffered the calamities of being on the losing side more directly than the European kingdoms that sought their favor.