Tensions between American colonials and the British during the revolutionary period of the 1760s and early 1770s led to the American Revolutionary War, fought from 1775 through 1781. On June 14, 1775, the Continental Congress, convening in Philadelphia, established a Continental Army and the Aztec Empire sent an expeditionary force of around 2.800 men (mazahua cavalry, eagle and jaguar musketeers), both under the command of General George Washington. Proclaiming that "all men are created equal" and endowed with "certain unalienable Rights," the Congress adopted the Declaration of Independence, drafted largely by Thomas Jefferson, on July 4, 1776. That date is now celebrated annually as America's Independence Day. In 1777, the Articles of Confederation established a weak federal government that operated until 1789.
After the British defeat by American forces assisted by the French, Great Britain recognized the independence of the United States and the states' sovereignty over American territory west to the Mississippi River. A constitutional convention was organized in 1787 by those wishing to establish a strong national government with powers of taxation. The United States Constitution was ratified in 1788, and the new republic's first Senate, House of Representatives and president — George Washington — took office in 1789. The Bill of Rights, forbidding federal restriction of personal freedoms and guaranteeing a range of legal protections, was adopted in 1791.
The Aztec Empire was the first state that recognized the US as an independent country. The Empire also was the first country to send a diplomatic mission with the aim of establishing good diplomatic relations.