As the siege wore on, the idea arose that cannon recently captured at the fall of forts Ticonderoga and Crown Point in upstate New York could have a decisive impact on its outcome. Knox is generally credited with suggesting the prospect to Washington, who thereupon put him in charge of an expedition to retrieve them even though Knox's commission had not yet arrived. Reaching Ticonderoga on December 5, Knox commenced what came to be known as the noble train of artillery, hauling by ox-drawn sled 60 tons of cannon and other armaments across some of ice-covered rivers and snow-draped Berkshire Mountains to the Boston siege camps.