The clash began on April 19, 1775 when more about 700 British soldiers were given what they thought were secret orders to destroy colonial military supplies in Concord, Massachusetts. Fortunately, thanks to a rather elaborate colonial intelligence network, led by the Sons of Liberty, the Patriots were aware that their supplies were at risk, and were able to move them to different locations long before the British began to move. Also, thanks to the daring rides of a few brave men, the colonial militia knew that an engagement with the British Army was imminent.
The first shots were fired just after dawn in Lexington, Massachusetts the morning of the 19th, the "Shot Heard Round the World." The colonial militia, a band of 500 men, were outnumbered and initially forced to retreat. The British army was able to press forward to Concord, where they searched for the supplies, only to come up empty handed.
While the British were searching, the American militia was able to reform, and they met the enemy at the North Bridge in Concord, and they were successful this time in driving the British back. As more American reinforcements arrived, they forced the British army south to Boston, and the militias blockaded the narrow land accesses to Charlestown and Boston, starting the Siege of Boston.
The American War for Independence was now in full swing.