The Seneca tribe of Western New York was the largest of the Six Nations, and its warriors second only to the Mohawk in courage and military prowess. Under Cornplanter, Guyasuta and other war captains they distressed a wide extent of territory in New York and Pennsylvania and decorated their huts with the scalps of hundreds of white persons.
Early in the summer of 1779, Washington directed that General John Sullivan lead a large force against the Iroquois country from the east, and in July Colonel Brodhead received permission to undertake a movement of cooperation up the Allegheny Valley.
The expedition consisting of 615 men under Colonel Brodhead left Pittsburgh August 11, 1779. Small garrisons were left to guard Forts Pitt, McIntosh, Crawford and Armstrong. A small band of Delaware accompanied the expedition, and acted as scouting parties under Captain Samuel Brady and Lieutenant Hardin.
The provisions were conveyed up the river by boats as far as the mouth of the Big Mahoning, where the supplies were taken from the boats, loaded on the horses, and the expedition proceeded under the most unfavorable conditions. The expedition here left the river and followed an Indian trail almost due north, through what is now Clarion county.
A few miles below Brokenstraw Creek occurred a fight with savages, near where Thompson is now situated. Lieutenant Hardin was leading the advance, with fifteen white scouts and eight Delaware, when they discovered more than thirty Seneca warriors coming down the river in seven canoes, under the famous Chief Guyasuta. Each party discovered the other at about the same time. The Seneca paddled for shore, threw off their shirts and prepared for battle, little aware of the number of their opponents.
Both sides took to trees and rocks and began a sharp fusillade, until a few minutes another party of scouts appeared, took the Seneca on the flank and poured a hot fire upon them. At the sound of this firing Colonel Brodhead formed his column so as to protect his pack train and then hurried forward with reinforcements. He arrived just in time to witness the retreat of the Seneca, who now realized the strength of the white force. Five Indians were killed and several wounded. Eight guns and seven canoes containing their blankets, shirts and provisions were prizes. Only three of Brodhead’s men were slightly wounded.
The army went into camp near the scene of the conflict and on the following morning moved to Brokenstraw Creek. Here Colonel Brodhead decided to leave his stores and baggage and march light to Conewago. A rude breastwork was constructed of fallen trees and bundles of faggots, on a high bluff which commanded an extensive view up and down the river. This post was garrisoned by an officer and forty men, while the expedition pushed on for Conewago. Upon arrival the Colonel was disappointed to find the Iroquois town deserted and their huts falling into decay.
After a hard march of twenty miles the army came again within sight of the Allegheny River, and from a hilltop they discovered a number of Indian villages, surrounded by great fields of splendid corn and patches of beans, squashes and melons. This Iroquois settlement extended for eight miles along the fertile bottom land of the Allegheny River, where the great Cornplanter reservation was afterwards established.
The Indian spies had discovered the approach of the American forces, and the warriors had fled so hastily with their women and children that they left behind many deer skins and other articles of value.
The Iroquois had long before this learned to build substantial log houses, even squaring the timbers as was the custom of the white pioneer settlers. In this village there were about 130 houses, some of them large enough to accommodate three or four families.