Which country recognized the United States in 1778 and later joined the war?

France recognized the United States in 1778, establishing a formal alliance during the American Revolutionary War. This recognition came after the Americans had declared their independence in 1776 and sought international support to bolster their cause against Great Britain. The alliance was significant as France provided military assistance, resources, and naval support, which played a crucial role in the eventual success of American forces. The Treaty of Alliance signed between France and the United States marked a pivotal moment in the war, solidifying France's commitment to aiding the colonists in their fight for independence.

This collaboration was vital for the American colonies, as France's involvement not only helped in terms of military strength but also offered legitimacy to the American cause on the world stage.