In the Union of Horodło, signed on 2 October 1413, he decreed that the status of the Grand Duchy of Lithuania was "tied to our Kingdom of Poland permanently and irreversibly" and granted the Catholic nobles of Lithuania privileges equal to those of the Polish szlachta.
Na unión de Horodłou, asinada o 2 de outubro de 1413, decretou que o Gran Ducado de Lituania quedaba «ligado ao noso reino de Polonia permanente e irreversiblemente» e concedeu á nobreza católica lituana os mesmos privilexios que os que tiña a szlachta polaca.