The major event in American history that took place in 1776 was the adoption of the Declaration of Independence on July 4. This document, primarily authored by Thomas Jefferson, proclaimed the thirteen American colonies' intention to separate from British rule due to grievances over taxation, lack of representation, and other perceived injustices. The Declaration articulated fundamental principles of democracy, emphasizing individual rights and the pursuit of happiness. Its adoption marked the formal beginning of the Revolutionary War and laid the ideological foundation for the United States. The Fourth of July is now celebrated annually as Independence Day, symbolizing freedom and national identity.