Powder Alarm - Expedition

Expedition

On August 31, Gage sent Middlesex County sheriff David Phips to Brattle with orders to remove the provincial powder; Brattle turned the key to the powderhouse over to Phips. Gage also gave orders to ready a force of troops for action the next day, something that did not go unnoticed by the local population. At some point that day, General Gage, whether by his intent, accident, or theft by a messenger, lost possession of William Brattle's letter; the widely held story is that it was dropped. News of its content spread rapidly, and many considered it to be a warning to Gage to remove the provincial powder before Patriots could seize it.

Early in the morning of September 1, a force of roughly 260 British regulars from the 4th Regiment, under the command of Lieutenant Colonel George Maddison, were rowed in secrecy up the Mystic River from Boston to a landing point near Winter Hill in modern-day Somerville. From there they marched about a mile to the Powder House, a gunpowder magazine that held the largest supply of gunpowder in Massachusetts. Phips gave the King's Troops the keys to the building, and after sunrise they removed all of the gunpowder. Most of the regulars then returned to Boston the way they had come, but a small contingent marched to Cambridge, removed two field pieces, and took them to Boston by foot over the Great Bridge and up Boston Neck. The field pieces and powder were then taken from Boston to the British stronghold on Castle Island, then known as Castle William (renamed Fort Independence in 1779).