The final treaty also voided Spanish guarantees of military support that colonial officials had made to Native Americans in the disputed regions, greatly weakening those communities' ability to resist encroachment upon their lands. The treaty represented a major victory for the Washington administration and placated many of the critics of the Jay Treaty. It also enabled and encouraged American settlers to continue their movement west, by making the frontier areas more attractive and lucrative. The region that Spain relinquished its claim to through the treaty was organized by Congress as the Mississippi Territory on April 7, 1798.