These representations could not efface from the bosoms of the Narraghansetts, that deep rooted enmity which neighbours, not bound together by ligaments of sufficient strength to prevent reciprocal acts of hostility, too often feel for each other. Dreading still less the power of a foreign nation, than that of men with whom they had been in the habit of contending, they not only refused to join the Piquods, but communicated their proposition to the government of Massachusetts, with whom they formed an alliance against that tribe. Open war being resolved on by both parties, Captain Underhill was sent to the relief of fort Saybrooke which had been besieged by the Indians; and the three colonies, Massachusetts, Plymouth, and Connecticut, agreed to march their united forces into the country of the Piquods, to effect their entire destruction. The troops of Connecticut were first in motion. Those of Massachusetts were detained by the controversy concerning the covenant of works, and of grace, which had insinuated itself into all the transactions of that colony. Their little army, when collected, found itself divided by this metaphysical point; and the stronger party, believing that the blessing of God could not be expected to crown with success the arms of such unhallowed men as their opponents in faith on this question, refused to march until their small band was purified by expelling the unclean, and introducing others whose tenets were unexceptionable.
While this operation was performing, the troops of Connecticut, reinforced by a body of friendly Indians and by a small detachment from Saybrooke, determined to march against the enemy. The Piquods had taken two positions which they had surrounded with palisadoes, and had resolved to defend. The nearest was on a small eminence surrounded by a swamp near the head of Mystic river. Against this fort the first attack was made. The Indians, deceived by a movement of the vessels from Saybrooke to Narraghansett, believed the expedition to have been abandoned; and celebrated, in perfect security, the supposed evacuation of their country. About day-break, while they were asleep, the English approached, and the surprise would have been complete, had they not been alarmed by the barking of a dog. They immediately gave the war whoop, and flew undismayed to arms. The English rushed to the attack, forced their way through the works, and set fire to the Indian wigwams. The confusion soon became general, and almost every man was killed or taken.