Grunwald 1410 - Book in English

Grand Master Ulrich von Jungingen did not loiter about. Forces of the Teutonic Order entered the Dobrzyn Land as early as August 16. This kind of "Blitzkrieg" occurred even before orders from Jagiello or his court could possibly reach these territories. By September 2, the Teutonic Knights captured all of the castles in that area: Dorzyn, Rypin, Lipno, Bobrowniki and Zlotoria. Some detachments approached Drezdenko and infiltrated and raided the Duchy of Masovia, which was allied with Poland, using the same plan of action they perfected earlier during their forays into Lithuania.
They also attacked Krajna, which was the northernmost boundary of the Kingdom of Poland, capturing the towns of Kamien and Sepolno. They encountered resistance from the garrison of Bydgoszcz, who even clashed victoriously against the army of the Teutonic Order and captured Heinrich von Plauen, the Komtur of Schwetz (Swiecie). Reinforcements soon arrived, however, capturing Bydgoszcz and setting the captive free – the very man whose role was the instrumental in preventing the Teutonic Order from complete destruction a year later…
It took a month for the Poles to gather their forces since the declaration of war. Led by Jagiello, they advanced towards the Dobrzyn Land. Two weeks later, on September 28, these forces arrived at the walls of Bydgoszcz and took the city by storm on October 6. This immediate action was necessitated by the fact Bydgoszcz was an important borderland staging area for the planned offensive campaign of the allied forces.