In the beginning of 1409 he concluded a treaty with Jagiello at Novogrudok for the purpose, and on the 9th cf July 1410 the combined Polish-Lithuanian forces, reinforced by Hussite auxiliaries,.
The Hussite wars, the feuds of Burgundian and Armagnac, the renewal of the Hundred Years' War, all prevented it from drawing new blood from the west.
The success of the Hussite raids in Germany gave fresh confidence to the Sla y s of Poland.
The city developed with great rapidity, and at the outbreak of the Hussite troubles, early in the 14th century, was next to Prague the most important in Bohemia, having become the favourite residence of several of the Bohemian kings.
By way of reprisals for the Hussite outrages in Prague, the miners of Kuttenberg seized on any Hussites they could find, and burned, beheaded or threw them alive into the shafts of disused mines.