Archbishop Albero of Trier turned fortresses into the foundation of his power, mastering the art of siege warfare in twelfth-century Germany. His campaigns reveal how battles were rare, but sieges shaped the reality of medieval war.
By David Bachrach
The bishops of the German Empire were notoriously bellicose, often leading their troops to war in the service of the king or in pursuit of the interests of their sees. For the most part, scholars have focused on the development of large military households by bishops, including substantial numbers of heavily armed, mounted troops of the type once thought to play a dominant role in the conduct of warfare in medieval Europe. In reality, however, German bishops found it necessary to focus most of their attention in military affairs on the defense and capture of fortifications. These strongholds, ranging in size from fortress cities of Roman origin to newfangled fortified towers, known in German as Bergfriede, numbered in the thousands throughout the Empire.
Numerous narrative sources from the twelfth century mention in passing the participation of German bishops, as well as abbots, in the conduct of war. However, a cleric named Balderich of Florennes (died c. 1163) decided to honor the memory of his former master, Archbishop Albero of Trier (1132–1152), with an account of his life. Balderich focused, in large part, on Albero’s “secular” activities, and particularly on his successful efforts to establish Trier as a de facto independent power. What emerges throughout this account is Albero’s mastery of siege warfare.
Restoring Trier’s Power Base
The opening folio in Balderich’s Gesta Alberonis – The Deeds of Albero of Trier – rier, Stadtbibliothek Weberbach Trier, Hs. 1387/6 8°
Balderich makes clear that Albero’s predecessors Meginher (1128–1130) and Gottfried (1124–1127) had left the archbishopric’s finances in terrible shape; they had mortgaged many of its estates and allowed many others to fall into the hands of Burgrave Ludwig, who was supposed to represent royal interests within the city of Trier itself. Among his first acts as archbishop, Albero restored the old archiepiscopal fortress at Pfalzel, located just across the Mosel River from Trier, which he used as his base of operations. Secure behind the walls of this erstwhile late Roman fortress, Albero successfully starved the burgrave into submission.
The next major challenge that Albero faced was an attack, probably in 1137, on the archiepiscopal fortress at Arras, located on a hill above the Mosel River, near the modern town of Alf. Count Otto of Rheineck as well as his brothers Werner and John sought to expand their power at the expense of the archbishop along the northeastern edge of his diocese. Their fortress at Nantersburg (today Entersburg) was located about 30 kilometers upstream on the Mosel from modern Alf and by gaining control over Burg Arras, they could control movement along this entire stretch of the river.
The brothers were initially successful in capturing Burg Arras but, as Balderich colorfully put it, Albero swore on his tonsure that he would not shave his beard until he had recaptured his stronghold, and torn Nantersburg down to its foundations. Albero successfully mobilized military forces from throughout the diocese and undertook simultaneous sieges of the two strongholds. Albero captured both, destroying Nantersburg as he had sworn to do, and reestablishing a garrison at Arras.
Two years later, Albero played a significant role in the election of Conrad, the Staufen duke of Franconia, as king (1139–1152). As a reward, Conrad returned control over the wealthy monastery of St. Maximin, located in Trier, which held estates throughout the Rhineland. To vindicate his rights there, however, the archbishop had to engage in a lengthy conflict with Count Henry IV of Luxemburg and Namur, who was the advocate of St. Maximin and did not want to give up this lucrative office.
Conflict with Count Henry of Luxemburg
Archbishop Albero of Trier depicted in the Gesta Alberonis
The conflict began when Count Henry led forces toward the city of Trier itself. The old Roman walls of the city were largely in disrepair. However, Henry was content to ravage the countryside rather than attack the city. Balderich asserted that it was Count Frederick of Vianden, a local notable, who convinced Henry to withdraw, saying that if Henry sacked the city, he would be held in infamy.
In response to the count’s initial attack, Archbishop Albero took decisive action, and led his forces to besiege one of Henry’s fortresses at a place called Mount Rudolf. After he captured and destroyed this stronghold, Albero constructed a new fortification nearby, which he garrisoned with his troops. Balderich stated that this site was of particular importance because Mount Rudolf was located in the heart of the archbishopric’s territory.
Subsequently, according to Balderich, Albero captured the count’s fortifications at Manderscheid, Gerland, and Zolver. The locations of the latter two fortresses have not been identified by scholars. However, Manderscheid, located just 25 kilometers to the west of Burg Arras, was an important forward outpost for Count Henry into the territory of Trier, and its capture helped to secure this region of the bishopric from attack from Henry’s center of strength in Namur.
Albero also captured the fortified monastery of Echternach, located just 20 kilometers west of Trier. Balderich stressed that Albero deployed a large garrison there, which served as a forward defense of his city. Finally, emphasizing the importance of the role that fortifications played in contemporary warfare, Balderich insisted, with obvious exaggeration, that the archbishop captured or destroyed an additional 30 strongholds held by Count Henry.
Henry sought to force Albero to break off the campaign of sieges by leading an army to the archiepiscopal fortress at Pfalzel, which he put under siege. This decision led to the one and only battle recorded by Balderich in which the archbishop took part. When Albero learned of Henry’s siege, he immediately broke off his operations and led his men on a night march to catch the count unprepared. However, Henry learned of Albero’s approach and fled with his troops. Henry retreated for two days before Albero caught up with him near the estate of Wittlach and forced a battle. The count’s forces were defeated, with most of his men captured or killed.
The last major military action of Albero’s pontificate also took place in the context of a siege. In 1148, Count Palatine Hermann sent forces to occupy the fortress of Treis, in the modern town of Treis-Karden along the Mosel. This stronghold belonged to the son of Albero’s old enemy Otto of Rheineck, also named Otto, who pledged to become his man if the archbishop could recover Treis for him. Balderich states that Albero immediately set out with his army and undertook a siege of the fortress, located about 80 kilometers northeast of Trier and just 20 kilometers from the archiepiscopal fortress at Arras. The possession of Treis would have significantly strengthened the archbishop’s military position along this frontier.
The count palatine responded by mobilizing an army to relieve the siege. Balderich gives a lengthy account of the activities of Albero’s troops while they waited for Hermann to take action. He specifically describes the training of the mounted troops to charge in formation, and then feign a retreat, with another group of men then charging and feigning retreat in turn. The archbishop’s army waited in readiness for three days before hearing word that the count palatine’s forces were advancing.
Albero summoned his men to take up their positions. Balderich states that despite his old age and physical weakness, the archbishop mounted his horse and personally directed the deployment of his troops. He then preached to his men, telling them that they were fighting on behalf of St. Peter, whose lands they were protecting, and that they would be strengthened by divine power. He called upon them all to confess their sins. After this public confession, Albero absolved them all and granted an indulgence, promising that if his troops died in battle that day, they would go directly to heaven. Finally, Albero took up his cross and led his army toward the enemy.
But there was no battle. Hermann, after seeing the size of the archbishop’s army, sent messengers to negotiate a settlement, and Albero gained possession of the fortress of Treis without a fight.
The account by Balderich, as much as he exaggerates the successes of his old master, nevertheless reveals the actual nature of warfare in this period. For every battle, there were numerous sieges. More often than not, the rather small number of battles that took place were the result of the effort to relieve a siege. Albero was successful in establishing Trier as a de facto independent state because he understood this fundamental reality and devoted his resources to protecting his own strongholds and seizing those of his enemies.
David Bachrach is a Professor at the University of New Hampshire, where he researches medieval military history, particularly in England and Germany.
Further Readings:
Graham A. Loud, “Slaying the Servants of the Lord: The Killing of Bishops in Medieval Germany, c. 900–1300,” English Historical Review 139 (2024), 579–612.
Archbishop Albero of Trier turned fortresses into the foundation of his power, mastering the art of siege warfare in twelfth-century Germany. His campaigns reveal how battles were rare, but sieges shaped the reality of medieval war.
By David Bachrach
The bishops of the German Empire were notoriously bellicose, often leading their troops to war in the service of the king or in pursuit of the interests of their sees. For the most part, scholars have focused on the development of large military households by bishops, including substantial numbers of heavily armed, mounted troops of the type once thought to play a dominant role in the conduct of warfare in medieval Europe. In reality, however, German bishops found it necessary to focus most of their attention in military affairs on the defense and capture of fortifications. These strongholds, ranging in size from fortress cities of Roman origin to newfangled fortified towers, known in German as Bergfriede, numbered in the thousands throughout the Empire.
Numerous narrative sources from the twelfth century mention in passing the participation of German bishops, as well as abbots, in the conduct of war. However, a cleric named Balderich of Florennes (died c. 1163) decided to honor the memory of his former master, Archbishop Albero of Trier (1132–1152), with an account of his life. Balderich focused, in large part, on Albero’s “secular” activities, and particularly on his successful efforts to establish Trier as a de facto independent power. What emerges throughout this account is Albero’s mastery of siege warfare.
Restoring Trier’s Power Base
Balderich makes clear that Albero’s predecessors Meginher (1128–1130) and Gottfried (1124–1127) had left the archbishopric’s finances in terrible shape; they had mortgaged many of its estates and allowed many others to fall into the hands of Burgrave Ludwig, who was supposed to represent royal interests within the city of Trier itself. Among his first acts as archbishop, Albero restored the old archiepiscopal fortress at Pfalzel, located just across the Mosel River from Trier, which he used as his base of operations. Secure behind the walls of this erstwhile late Roman fortress, Albero successfully starved the burgrave into submission.
The next major challenge that Albero faced was an attack, probably in 1137, on the archiepiscopal fortress at Arras, located on a hill above the Mosel River, near the modern town of Alf. Count Otto of Rheineck as well as his brothers Werner and John sought to expand their power at the expense of the archbishop along the northeastern edge of his diocese. Their fortress at Nantersburg (today Entersburg) was located about 30 kilometers upstream on the Mosel from modern Alf and by gaining control over Burg Arras, they could control movement along this entire stretch of the river.
The brothers were initially successful in capturing Burg Arras but, as Balderich colorfully put it, Albero swore on his tonsure that he would not shave his beard until he had recaptured his stronghold, and torn Nantersburg down to its foundations. Albero successfully mobilized military forces from throughout the diocese and undertook simultaneous sieges of the two strongholds. Albero captured both, destroying Nantersburg as he had sworn to do, and reestablishing a garrison at Arras.
Two years later, Albero played a significant role in the election of Conrad, the Staufen duke of Franconia, as king (1139–1152). As a reward, Conrad returned control over the wealthy monastery of St. Maximin, located in Trier, which held estates throughout the Rhineland. To vindicate his rights there, however, the archbishop had to engage in a lengthy conflict with Count Henry IV of Luxemburg and Namur, who was the advocate of St. Maximin and did not want to give up this lucrative office.
Conflict with Count Henry of Luxemburg
The conflict began when Count Henry led forces toward the city of Trier itself. The old Roman walls of the city were largely in disrepair. However, Henry was content to ravage the countryside rather than attack the city. Balderich asserted that it was Count Frederick of Vianden, a local notable, who convinced Henry to withdraw, saying that if Henry sacked the city, he would be held in infamy.
In response to the count’s initial attack, Archbishop Albero took decisive action, and led his forces to besiege one of Henry’s fortresses at a place called Mount Rudolf. After he captured and destroyed this stronghold, Albero constructed a new fortification nearby, which he garrisoned with his troops. Balderich stated that this site was of particular importance because Mount Rudolf was located in the heart of the archbishopric’s territory.
Subsequently, according to Balderich, Albero captured the count’s fortifications at Manderscheid, Gerland, and Zolver. The locations of the latter two fortresses have not been identified by scholars. However, Manderscheid, located just 25 kilometers to the west of Burg Arras, was an important forward outpost for Count Henry into the territory of Trier, and its capture helped to secure this region of the bishopric from attack from Henry’s center of strength in Namur.
Albero also captured the fortified monastery of Echternach, located just 20 kilometers west of Trier. Balderich stressed that Albero deployed a large garrison there, which served as a forward defense of his city. Finally, emphasizing the importance of the role that fortifications played in contemporary warfare, Balderich insisted, with obvious exaggeration, that the archbishop captured or destroyed an additional 30 strongholds held by Count Henry.
Henry sought to force Albero to break off the campaign of sieges by leading an army to the archiepiscopal fortress at Pfalzel, which he put under siege. This decision led to the one and only battle recorded by Balderich in which the archbishop took part. When Albero learned of Henry’s siege, he immediately broke off his operations and led his men on a night march to catch the count unprepared. However, Henry learned of Albero’s approach and fled with his troops. Henry retreated for two days before Albero caught up with him near the estate of Wittlach and forced a battle. The count’s forces were defeated, with most of his men captured or killed.
The Siege of Treis and Albero’s Final Campaigns
The last major military action of Albero’s pontificate also took place in the context of a siege. In 1148, Count Palatine Hermann sent forces to occupy the fortress of Treis, in the modern town of Treis-Karden along the Mosel. This stronghold belonged to the son of Albero’s old enemy Otto of Rheineck, also named Otto, who pledged to become his man if the archbishop could recover Treis for him. Balderich states that Albero immediately set out with his army and undertook a siege of the fortress, located about 80 kilometers northeast of Trier and just 20 kilometers from the archiepiscopal fortress at Arras. The possession of Treis would have significantly strengthened the archbishop’s military position along this frontier.
The count palatine responded by mobilizing an army to relieve the siege. Balderich gives a lengthy account of the activities of Albero’s troops while they waited for Hermann to take action. He specifically describes the training of the mounted troops to charge in formation, and then feign a retreat, with another group of men then charging and feigning retreat in turn. The archbishop’s army waited in readiness for three days before hearing word that the count palatine’s forces were advancing.
Albero summoned his men to take up their positions. Balderich states that despite his old age and physical weakness, the archbishop mounted his horse and personally directed the deployment of his troops. He then preached to his men, telling them that they were fighting on behalf of St. Peter, whose lands they were protecting, and that they would be strengthened by divine power. He called upon them all to confess their sins. After this public confession, Albero absolved them all and granted an indulgence, promising that if his troops died in battle that day, they would go directly to heaven. Finally, Albero took up his cross and led his army toward the enemy.
But there was no battle. Hermann, after seeing the size of the archbishop’s army, sent messengers to negotiate a settlement, and Albero gained possession of the fortress of Treis without a fight.
The account by Balderich, as much as he exaggerates the successes of his old master, nevertheless reveals the actual nature of warfare in this period. For every battle, there were numerous sieges. More often than not, the rather small number of battles that took place were the result of the effort to relieve a siege. Albero was successful in establishing Trier as a de facto independent state because he understood this fundamental reality and devoted his resources to protecting his own strongholds and seizing those of his enemies.
David Bachrach is a Professor at the University of New Hampshire, where he researches medieval military history, particularly in England and Germany.
Further Readings:
Graham A. Loud, “Slaying the Servants of the Lord: The Killing of Bishops in Medieval Germany, c. 900–1300,” English Historical Review 139 (2024), 579–612.
Benjamin Arnold, “German Bishops and Their Military Retinues in the Medieval Empire,” German History 7.2 (1989), 161–183.
A Warrior Bishop of the Twelfth Century: The Deeds of Albero of Trier by Balderich, translated with an introduction and notes by Brian A. Pavlac (Toronto, 2008).
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