Siege of Marienburg (1410): The Teutonic Knights' Desperate Stand
Between July 26 and September 19, 1410, the combined armies of Poland and Lithuania besieged Marienburg Castle, capital of the Teutonic Order's monastic state, hoping to finish off the Knights after crushing them at the Battle of Grunwald weeks earlier. Despite overwhelming momentum, King Władysław II Jagiełło and Grand Duke Vytautas failed to take the fortress, allowing the Teutonic Order to survive and negotiate the far less punishing Peace of Thorn in 1411 rather than face total annihilation.
From Grunwald to the Gates of Marienburg
On July 15, 1410, the Battle of Grunwald delivered one of the most catastrophic defeats in the Teutonic Order's history, killing Grand Master Ulrich von Jungingen along with much of the Order's leadership and army. With the Knights' military strength shattered, the road into Prussia lay open, and the joint Polish-Lithuanian forces marched toward Marienburg, the Order's administrative and spiritual capital on the Nogat River. Jagiełło and Vytautas moved deliberately rather than urgently, however, allowing the Teutonic Knights precious days to reorganize. This delay proved consequential: it gave Heinrich von Plauen, the comturship of Schwetz, time to rush reinforcements into Marienburg and take command of its defense before the besiegers arrived on July 26, 1410. Von Plauen's foresight in strengthening the garrison and securing the castle's massive brick walls transformed what might have been a swift capitulation into a grueling two-month standoff that would ultimately determine the Order's survival.
Did You Know?
Heinrich von Plauen was not the Teutonic Order's designated commander before the siege—he was the comtur of Schwetz who took initiative to defend Marienburg after the disaster at Grunwald, and his successful defense earned him election as Grand Master, a position he held until 1413.
The Two-Month Siege
Marienburg was no ordinary fortress. As one of the largest brick castles in medieval Europe, its concentric walls, moats, and towers had been built over more than a century to withstand exactly this kind of assault. Von Plauen organized a disciplined defense, rallying the garrison and civilian population while Polish and Lithuanian forces encircled the castle and attempted various methods of bombardment and blockade. The besiegers lacked the heavy siege equipment and unified resolve needed to breach such formidable defenses, and disease began spreading through their camp as the weeks dragged on. Vytautas, whose Lithuanian troops bore much of the campaign's burden, grew increasingly frustrated with the stalemate and concerned about threats to his own eastern territories from the Golden Horde. Political tensions between the Polish and Lithuanian commanders further complicated the siege effort. Meanwhile, von Plauen's leadership galvanized the defenders, and other Teutonic strongholds across Prussia began organizing resistance, forcing the besieging armies to divert attention and resources. By mid-September, with autumn approaching, supplies dwindling, and Vytautas withdrawing his forces on September 18, Jagiełło recognized the siege was unwinnable and lifted it on September 19, 1410.
Aftermath and the Peace of Thorn
The failure to capture Marienburg proved a pivotal moment in medieval European history. Had the castle fallen, the Teutonic Order likely would have ceased to exist as a political entity, and Prussia might have been absorbed entirely into the Polish-Lithuanian union. Instead, Heinrich von Plauen's successful defense preserved the Order's core territory and bought time for reorganization. He was elected Grand Master shortly after the siege, tasked with rebuilding an institution devastated by Grunwald's losses. When peace negotiations concluded with the Treaty of Thorn on February 1, 1411, the Teutonic Knights ceded only modest territorial concessions, including Samogitia (temporarily, during Vytautas's and Jagiełło's lifetimes) and the Dobrzyń Land, while retaining most of their Prussian lands. The Order did face crushing war reparations that strained its finances for years, but it survived as a sovereign state for another century. Von Plauen's stand at Marienburg thus stands as one of history's notable examples of a fortress siege reversing the trajectory of a war, transforming near-total defeat into a manageable, if costly, negotiated settlement.