The royal authorities in Boston had seen these increasing numbers of militia appearing and thought that the militia would not interfere if they sent a sizable force to Concord to seize munitions and stores there (which they considered the King's property, since it was paid for to defend the colonies from the American Indian threat). The British officers were proven wrong. Shooting erupted at Lexington. There is still a debate as to whether it was a colonist or a British soldier who fired the first shot. The militia left the area, and the British moved on. The British then moved to Concord and faced a larger number of militia. The British were rapidly outnumbered at Concord, with the arrival of the slower moving militia; they had not counted on a long fight, and so had not brought additional ammunition beyond the standard issue in the soldiers' cartridge boxes. This then forced a strategic defeat on Colonel Smith, forcing him back to Boston.