 The agreement made possible a close cooperation between the two nations necessary to succeed in struggles with the Teutonic Order.The Union of Horodło of 1413 defined the relationship further and granted privileges to the Roman Catholic (as opposed to Eastern Orthodox) segment of the Lithuanian nobility.The Polish–Lithuanian–Teutonic War of 1409–1411, precipitated by the Samogitian uprisings in Lithuanian territories controlled by the State of the Teutonic Order, culminated in the Battle of Grunwald (Tannenberg), in which the combined forces of the Polish and Lithuanian-Rus' armies completely defeated the Teutonic Knights.