Unlike his brother, Ulrich's diplomatic capability was limited. The situation in Samogitia remained tense, incited by Grand Duke Vytautas, who intended to make use of the turmoils to regain the ceded lands. Furthermore, the new Grand Master had inherited the rising conflict with Vytautas' cousin King Jagiello of Poland over Dobrzyń Land and the pawned Neumark region. The Polish ambassador Archbishop Mikołaj Kurowski declared, that any attack on Lithuania would inevitably entail an armed conflict with Poland. Despite the threat of a two-front war, Ulrich prepared for a preemptive strike. He forged an alliance with King Sigismund of Hungary, levied mercenaries in the Holy Roman Empire, and on 6 August 1409 declared war against Poland.