Teutonic Armies, Fortresses and Frontiers: How the Order Organized Warfare

The Teutonic Order began as a hospital brotherhood in Acre around 1190 and became a military order in 1198. Its warfare later centred on two distinct Baltic regions: Prussia, where the Order established its rule from 1230, and Livonia, where it absorbed the Livonian Brothers of the Sword in 1237. In both regions, the Order’s armies served a territorial purpose. They fought campaigns, guarded strongholds and helped maintain authority across dispersed lands. Those forces were not made up solely of professed knight-brothers: they also included local levies, temporary crusaders and paid soldiers.

Prussian and Livonian military arrangements were related but not identical. Prussia came under the Grand Master’s direct government after he moved his seat to Marienburg in 1309. Livonia retained a separate administration under its own Landmeister, or territorial master. The Prussian branch was secularized in 1525, while the Livonian Order continued until the political settlement of 1561. The military system described here belongs chiefly to those medieval territorial branches.

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Who served in the Order’s armies?

The professed brothers formed the Order’s permanent religious and governing core. Knight-brothers were the fighting members most closely associated with its military role. Priest-brothers served the Order as clergy, while Sariant-brothers were armed soldiers who were not knight-brothers. Half-brothers generally worked in economic and care-related roles. These different forms of service meant that an Order house and its military resources depended on more than a small body of armoured knights.

The brothers were supplemented by troops drawn from beyond the Order. In Prussia, these included local feudal levies, among them Prussian peasant contingents, as well as the retinues of the brothers. Rulers and nobles allied to the Order could also provide forces. The size of a campaign depended on the levies and allied forces that answered its call.

Guest crusaders were another important source of manpower. They travelled from different parts of Europe to join campaigns, often on a seasonal basis, and then returned home. At the Battle of Grunwald in 1410, the Order’s army included men from numerous regions, including Westphalia, Frisia, Austria, Swabia and Bavaria. The presence of such visitors could add considerable strength to a campaign, but it did not give the Order a reliable body of long-term soldiers.

Paid troops helped fill that gap. Mercenaries, many recruited from German lands within the Holy Roman Empire, served alongside the brothers and other contingents. The Order’s reliance on hired soldiers increased as the religious rationale for campaigning weakened and fewer volunteers arrived for crusades. Mercenaries could provide experienced fighters, but their employment was costly. At Grunwald, the Order’s army also included heavy cavalry and artillery. Even there, however, armoured knight-brothers made up only a small part of the whole force.

Command across Prussia and Livonia

The Order’s command structure combined central officers with territorial and local administration. The Grand Master headed the Order, while the Grand Marshal was responsible for military affairs. Other senior officers managed finances, clothing and armament, and the Order’s commercial business. The treasurer oversaw money; the Trapier was responsible for clothing and equipment; and the trading officer known as the Großschäffer managed commercial activity that included procurement and credit.

Commanderies provided a local framework for governing and supporting the Order’s lands. Each was headed by a Komtur, or commander, who administered the district and its subordinate areas. These districts connected the central leadership to local resources and personnel. They were not simply military garrisons: they were also units of territorial government, with economic and administrative responsibilities that helped sustain military activity.

In Prussia, the Grand Master’s move to Marienburg made him the territory’s central ruler. Earlier, a separate Prussian Landmeister had governed the region; after 1309, that office was combined with the Grand Master’s position. Livonia followed a different pattern. Its Landmeister remained the senior authority there, and the Livonian branch maintained substantial autonomy from Prussia. The two regions shared an institutional origin, but they did not operate as a single, uniformly directed military province.

Fortresses as bases for defence and control

Fortresses helped the Order hold territory as well as defend it. They served as protected centres from which forces could respond to attacks, maintain a presence in contested districts and support campaigns. In Prussia, the Order built and occupied strongholds during its conquest of Old Prussian lands and its later conflicts with Poland and Lithuania. Their military value depended on their place within a wider network of settlements, commanderies and routes, rather than on any one fortress acting alone.

The frontier could be difficult to defend everywhere at once. During preparations for the 1410 campaign, the Order concentrated its main force at Schwetz, while leaving garrisons in eastern castles including Ragnit, Rhein and Memel. This arrangement reflected the need to guard several possible approaches while keeping a mobile force available. It also shows why castles mattered as fixed points in a defence system: they could hold key locations even when the main army was elsewhere.

Strongholds could remain strategically important after a field army suffered defeat. Following Grunwald, the Polish-Lithuanian army besieged Marienburg, the Order’s capital, but failed to take it. The fortress’s defence helped the Order survive a severe military and political crisis. The victory in the field had not, by itself, secured the opposing army’s control of the Order’s territory.

Paying for campaigns and supplying strongholds

Military operations depended on the Order’s wider economy. Estates and farms associated with its houses produced food and supported livestock, including horses. Because frontier strongholds were exposed, some of their supporting farms lay farther inland. The estate serving Ragnit, for example, was at Labiau, about 80 kilometres away. This arrangement placed agricultural resources at some distance from the most vulnerable posts, while making reliable transport between the countryside and the frontier essential.

The Order also drew on revenue from its cities and its trade. Prussian towns such as Danzig, Elbing, Thorn and Königsberg were connected to Baltic commerce, and the Order’s economic resources helped maintain troops. Rivers and waterways were especially useful in a region of wetlands and extensive watercourses. Bridges and ferry crossings linked routes over land, while shipping connected the Baltic and inland centres. Supplies and reinforcements could also travel through Pomerelia into Prussia from territories to the west.

These resources did not remove the costs and risks of campaigning. A force assembled with guest crusaders could be larger than the Order’s permanent manpower, but those visitors served for limited periods. Hired troops offered another source of strength, but strained the treasury. Local levies and garrisons could support territorial defence, yet still depended on political cooperation and the resources available in their districts.

Different military settings in Livonia

Livonia had its own command structure and faced a different combination of opponents from Prussia. After the Livonian Brothers of the Sword joined the Teutonic Order in 1237, their former territory became the Livonian branch. It campaigned against Baltic peoples, including the Curonians and Semigallians, and faced conflict with Novgorod. In 1242, Livonian forces were defeated at the Battle on the Ice by the army of Prince Alexander Nevsky. Later, the Order suppressed a major Estonian revolt in 1343–1345.

These conflicts were managed under Livonia’s Landmeister, not simply by extending the Prussian command system northward. Livonia was also part of a wider political landscape that included ecclesiastical territories and the city of Riga. The branch’s autonomy and its separate territorial structure shaped how the Order administered military forces there. Bishops, vassals and towns supplied forces through their own political relationships, alongside the Livonian branch’s brethren.

From conquest to costly territorial warfare

The purpose of the Order’s warfare changed over time. In the thirteenth century, campaigns in Prussia accompanied conquest and the establishment of the Order’s rule. After the subjugation of the Prussians, conflict increasingly involved neighbouring Christian powers, especially Poland and Lithuania. The Lithuanian campaigns continued for generations, and western European knights still travelled to Prussia for seasonal expeditions. After Lithuania’s conversion to Christianity, however, the religious justification for such campaigns became harder to sustain.

The defeat at Grunwald in 1410 exposed the risks of this military system. The Order lost much of its senior leadership, but the defence of Marienburg prevented an immediate collapse. The settlement of 1411 imposed heavy payments, which the Order struggled to meet. It raised taxes, contributing to unrest among towns and landholders. Later conflict, including the Thirteen Years’ War, further weakened the Order’s position in Prussia. Under the Second Peace of Thorn in 1466, it lost extensive western territories and accepted the Polish Crown’s overlordship over its remaining Prussian lands.

In 1525, Grand Master Albert of Brandenburg secularized the Prussian territory and established the Duchy of Prussia under the Polish Crown. Livonia’s Order branch survived longer, but its rule ended in 1561 amid the region’s political and religious upheavals. The military history of the Teutonic Order was therefore not the story of one unchanging army. It was a changing system of professed brothers, local forces, foreign visitors, hired soldiers and fortified centres, shaped by distinct political conditions in Prussia and Livonia.