As Governor, he formulated Maxwell's Code (named after its printer, William Maxwell), the first written laws of the territory. He also sought to end Native American claims to Ohio land and clear the way for white settlement. In 1789, he succeeded in getting certain Native Americans to sign the Treaty of Fort Harmar, but many native leaders had not been invited to participate in the negotiations, or had refused to do so. Rather than settling the Native Americans' claims, the treaty provoked them to further resistance in what is also sometimes known as the "Northwest Indian War" (or "Little Turtle's War"). Mutual hostilities led to a campaign by General Josiah Harmar, whose 1,500 militiamen were defeated by the Native Americans in October 1790.