The United States Declaration of Independence was written by Thomas Jefferson at the behest of John Adams. It declared to the world that the 13 former British Colonies no longer accepted the rule (or protection) of Great Britain. Which is fair enough considering that they were at war with Great Britain at the time, and no longer wanted to be part of the British Empire. Maybe it was the quartering, the taxing or again, the cricket.
It was adopted by Congress on July 4th 1776, over a year after the outbreak of the American Revolutionary War.