Also, after the outbreak of the war of 1409–1410 between Poland, Lithuania and the Teutonic Order, the attitude of the Masovian Duke wasn't clear: in one side, he tried to contact King Sigismund of Hungary and by other side, he pressured his warring neighbors to maintain the peace.
Juga, setelah pecahnya peperangan tahun 1409–1410 di antara Polandia, Lituania dan Ordo Teutonik, sikap Adipati Masovia itu tidak jelas: di satu pihak, ia mencoba untuk menghubungi Raja Sigismund dari Hongaria dan di sisi lain, ia menekan tetangganya untuk mempertahankan perdamaian.