Winrich of Kniprode, grand master of the Order, was completing his plans for the destruction of this castle, when Duke Leopold of Austria arrived at Marienburg with his brilliant array of knights—a strong and welcome reinforcement. The route of the army took them past both the castles of Wielun and Pisten, which were left unmolested. A landing was effected upon the island of Kauen, and a camp was established in which all the supplies were stored. A bridge of boats was also constructed to the right bank of the Niemen, where the castle stood upon a tongue of land—upon the spot where now stands the city of Kovno.[11] The building of this bridge took three days, and before it was finished Kynstutt appeared with an army for the relief of the castle. He fell back, however, after a brief encounter and occupied the heights on the land side, east of the castle. To prevent him from making a sudden descent upon the camp, a breastwork of stone and wooden stakes was made, stretching in the shape of a bow from the Vilia to the Niemen. The flower of the army was placed in this intrenched camp. Another part was assigned to guard the supplies, and the remainder occupied themselves with the management of the siege machines. Missiles from the castle could not reach far enough to disturb the work, which progressed under the direction of a master smith and carpenter.