Throughout the mid 1700s the British enacted several pieces of legislation which tightly corralled the colonials. These included the Stamp Act in 1765 and the Tea Act in 1773. One of the final measures was the Coercive Acts, passed in 1774, also known as the "intolerable acts" by the colonists. This act established greater British control of Boston and instituted a more formal military rule throughout the colonies.
It is quite probable the Act alone would have eventually forced the colonies to declare independence, but not certain. It is also possible the colonies would have sent an envoy to the Crown in an attempt to negotiate colonial rule. However, in April 1775 Thomas Gage, British Governor of Massachusetts, sent British troops to Lexington, a known storage arsenal for colonial militia. It was here the first shots of the Revolutionary War were fired, although it was not even then officially known as a "war." This is the "shot heard around the world," but it is uncertain which side fired the first volley.