Early in the American Revolutionary War, Phelps was chosen as a member of "Committee of War for the expedition to capture Ft. Ticonderoga and Crown Point." The committee considered the advisability of taking Fort Ticonderoga, then occupied by the British, and in which there was stored a large amount of heavy artillery and other war implements. Capt. Phelps, Barnard Romance, Ephraim Buell, and Capt. Edward Mott, with others, composed this committee, Capt. Mott acting as chairman. They raised £300 (in today's value, € or US$ ) from the Public Treasury, though guaranteed by several patriotic gentlemen. This fund was placed in the hands of Capt. Phelps and Barnard Romance, with the request that they should go north and press forward this project. This resulted in the great and bloodless victory — the capture of Fort Ticonderoga.