General Thomas Gage, the new military governor, arrived in Boston on the 13th May 1774. He heard that the American colonists were building up their number of guns. His spies told him that their ammunition, gunpowder and other supplies were growing daily in Concord. They at least, Gage thought, could be destroyed.

Under cover of night, on the 18th of April 1775, he sent six British companies out from Boston towards Concord.

When the rebel leaders heard that Gage's troops were on the move, they suspected that Concord was in danger.
They were also worried that the British would capture, in near-by Lexington, two leading Revolutionaries from Boston, Samuel Adams, and the young, rich John Hancock. They asked Paul Revere and a friend of his, William Dawes, to spread the warning throughout the countryside.

When the six hundred British troops got to Lexington they found the road into town blocked by American (Minutemen) soldiers. The British leader ordered his men not to fire unless fired upon. Someone fired a musket though, and the fighting began.

The British defeated the Minutemen and then marched on to Concord and destroyed what arms they could find. The worst fighting though, occurred while  the British were marching back to Boston. All the way back, Minutemen snipers were hiding. They picked off nearly three hundred 'Redcoats'.

When the British got back to Boston, they built a line of defence across the road because more American soldiers came from the East and South. They attacked the British and kept them locked up in Boston.