In 1778, the British government encouraged loyal colonists and Native American allies to attack frontier settlements. In July, Major John Butler led an attack on the Wyoming Valley that left more than 300 patriot soldiers dead and, by Butler's estimate, destroyed 1,000 homes. The July attacks on the Wyoming Valley and the November deaths of women and children at Cherry Valley left the most enduring impressions of the frontier warfare of 1778. Many New York communities panicked and demanded help, and Congress concluded that only a major offensive expedition could successfully protect frontier communities. Thayendanegea, also known as Joseph Brant, was a young Mohawk leader and British captain who formed a corps of Native American and loyalist volunteers; although he was a force of restraint, Americans associated his name with the worst violence and alleged atrocities of the frontier warfare. Periodic attacks on the frontiers of New York and Pennsylvania in 1778 terrified exposed communities and prompted appeals to Congress to send Continental soldiers to aid in their defense. In late 1777, Major John Butler assembled loyal colonists who had fled New York's Mohawk Valley, and Butler's Rangers repeatedly attacked the frontier communities of New York and Pennsylvania throughout the rest of the war.