The Union of Vilnius and Radom of 1401 confirmed the status of Vytautas as grand duke under Władysław's overlordship, while assuring the title of grand duke to the heirs of Władysław rather than those of Vytautas: should Władysław die without heirs, the Lithuanian boyars were to elect a new monarch. Since no heir had yet been produced by either monarch, the implications of the union were unforeseeable, but it forged bonds between the Polish and Lithuanian nobility and a permanent defensive alliance between the two states, strengthening Lithuania's hand for a new war against the Teutonic Order in which Poland officially took no part. While the document left the liberties of the Polish nobles untouched, it granted increased power to the boyars of Lithuania, whose grand dukes had till then been unencumbered by checks and balances of the sort attached to the Polish monarchy. The Union of Vilnius and Radom therefore earned Władysław a measure of support in Lithuania.