At the time of the Siege of Boston, the Continental Army at Cambridge, Massachusetts, in June 1775, is estimated to have numbered from 14 to 16,000 men from New England (though the actual number may have been as low as 11,000 because of desertions). Until Washington's arrival, it remained under the command of Artemas Ward. The British force in Boston was increasing by fresh arrivals. It numbered then about 10,000 men. The British controlled Boston, and defended it with their fleet, but were outnumbered and did not attempt to challenge the American control of New England. Washington selected young Henry Knox, a self educated strategist, to take charge of the artillery from an abandoned British fort in upstate New York, and dragged across the snow to and placed them in the hills surrounding Boston in March 1776. The British situation was untenable. They negotiated an uneventful abandonment of the city, and relocated their forces to Halifax in Canada. Washington relocated his army to New York. For the next five years, the main bodies of the Continental and British armies campaigned against one another in New York, New Jersey, and Pennsylvania. These campaigns included the notable battles of Trenton, Princeton, Brandywine, Germantown, and Morristown, among many others.