As the British column approached Lexington Center, it broke into a run and was saved by a brigade of a thousand fresh troops armed with two cannon under Earl Percy, whose order to fire scattered the Colonists and allowed the beleaguered British troops to regroup. The British force then numbered 1,700 and continued through Lexington into Menotomy, present-day Arlington, while the Colonial force had grown to nearly 4,000. The fiercest fighting of the day took place there, and the fighting continued into Cambridge. By sundown, the exhausted British troops reached the military safety of Boston harbor after marching 20 miles out to Concord and fighting 20 miles back in less than 24 hours. By day's end, 273 British regulars and 94 Colonists were killed, wounded or missing. Not all of the Colonial troops who came together on Battle Road returned home that evening; many stayed, and campfires sprang up in a ring around Boston as the Siege of Boston began. The events of April 19, 1775 were only a beginning, and only after years of struggle would the American nation finally emerge.