U.S. History Timeline By educdianacisneros Nov 28, 1441 First appearance of slaves Jun 2, 1771 The Quartering of Troops Act was ratified Dec 16, 1773 The Boston Tea Party May 11, 1775 The American Revolutionary War begins Jul 4, 1776 Congress adopts the Declaration of Independance Sep 6, 1783 The American Revolutionary War ends Sep 17, 1787 The U.S. Constitution was signed Feb 17, 1801 Thomas Jefferson is elected president of the United States, won over John Adams Aug 4, 1820 Harriet Tubman was born Jul 20, 1855 The Underground Railroad was built Dec 10, 1948 the Universal Declaration of Human Rights is adopted and prohibited slavery