The Declaration of Independence was signed on July 4, 1776. There were battles fought as early as 1775. In 1775, April 19 to be exact, the Battle of Lexington-Concord was fought. There were many casualties in this battle. While war hadn't been officially declared, blood had been shed. It is possible to go further back to reference conflict. For example, you could say the Boston Massacre was a battle or clash between the colonists and the British soldiers. This was on March 5, 1770. You could also say the Boston Tea Party was also an example of a clash. This was on December 16, 1773. Thus depending on how you view the conflict, you could go as far back as March 5, 1770. Most people would say the Battle of Lexington-Concord, on April 19, 1775, was the first unofficial battle of the Revolutionary War. This would be between 14-15 months before the Declaration of Independence was signed.