Polish–Lithuanian–Teutonic WarŠiauliai, Lithuania
In December 1408, Władysław and Vytautas held strategic talks in Navahrudak Castle, where they decided to foment a Samogitian uprising against Teutonic rule to draw German forces away from Pomerelia. Władysław promised to repay Vytautas for his support by restoring Samogitia to Lithuania in any future peace treaty. The uprising, which began in May 1409, at first provoked little reaction from the Knights, who had not yet consolidated their rule in Samogitia by building castles; but by June their diplomats were busy lobbying Władysław's court at Oborniki, warning his nobles against Polish involvement in a war between Lithuania and the Order. Władysław, however, bypassed his nobles and informed new Grand Master Ulrich von Jungingen that if the Knights acted to suppress Samogitia, Poland would intervene. This stung the Order into issuing a declaration of war against Poland on 6 August, which Władysław received on 14 August in Nowy Korczyn.