Lost 11th-Century Castle Discovered in Swiss Countryside

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A previously unknown medieval castle has emerged from the Swiss landscape after a researcher studying high-resolution terrain maps identified telltale features of an early fortification near Uesslingen-Buch in northeastern Switzerland. The discovery of this 10th to 11th-century castle site, confirmed by the Thurgau Office of Archaeology, represents a significant addition to our understanding of medieval settlement patterns in the region and may finally solve a centuries-old historical puzzle about the location of a lost fortress destroyed in 1079.

The breakthrough came when a castle researcher from Canton Bern was analyzing LiDAR-derived terrain maps on his computer, searching for distinctive landscape formations that might indicate forgotten fortifications. What he found were two small plateaus surrounded by steep defensive ditches, located just under one kilometer west of the Kartause Ittingen monastery. According to archaeologists, these features are characteristic of motte-and-bailey castles, an early form of medieval defensive architecture that spread across northern Europe from the 10th century onwards.

LiDAR Technology Reveals Hidden History

The use of LiDAR technology (Light Detection and Ranging) has revolutionized archaeological discovery in recent years, allowing researchers to peer through vegetation and identify subtle terrain features invisible to the naked eye. In this case, the high-resolution relief maps revealed not only the castle plateaus but also several old hollow ways – ancient sunken pathways worn deep into the landscape by centuries of foot traffic and cart travel. These hollow ways, radiating from the castle site, provide crucial evidence of the medieval transportation network that once connected this fortress to the surrounding region.

Following the initial discovery from the digital terrain analysis, the Thurgau cantonal archaeology office authorized a metal detector survey of the identified location. Heritage Daily reports that this search yielded compelling physical evidence: pottery shards, several iron objects, and most significantly, three medieval projectile points – arrowheads that tell of the military function of this forgotten stronghold. These artifacts confirm the site’s occupation during the early medieval period and align with historical records describing castle warfare in the region.

A Castle Lost to History, Now Found

Historical documents add a tantalizing dimension to this discovery. According to written sources, a castle at the location known as Tbeli was destroyed in 1079 during a violent conflict between Abbot Eckehard II of Reichenau and Abbot Ulrich III of St. Gallen. The fortress was later reconstructed by the Lords of Ittingen, but its precise location was never specified in contemporary texts, creating a mystery that has puzzled historians for centuries. Archaeologists have long debated three possible sites for the Ittingen stronghold: the Chrzbuck castle mound in Warth-Weiningen, the grounds of the Ittingen Charterhouse itself, and now this newly identified location at Tbeli.

Ittingen Charterhouse, Uesslingen-Buch, Switzerland.

Ittingen Charterhouse, which is situated just 1km from the newly detected castle site. (CC BY-SA 3.0)

Adding further intrigue, a papal document from 1152 grants the Ittingen brothers permission to build a monastery on their castle grounds, suggesting that at least part of the medieval fortifications once stood where the Ittingen Charterhouse sits today. The newly discovered castle may represent an earlier phase of lordly settlement in the area, predating the later monastic complex. Based on comparable findings from other early medieval castles in the region, archaeologists believe the Tbeli fortress would have consisted of a multi-story wooden tower, protected by a defensive wooden palisade and surrounded by deep ditches designed to slow attackers and make the approach treacherous.

Motte-and-Bailey Castles: Engineering Medieval Defense

Motte-and-bailey castles represented a revolutionary approach to military architecture in the early medieval period. These fortifications could be constructed relatively quickly with unskilled labor, making them ideal for lords seeking to establish control over newly conquered or contested territories. The basic design consisted of two main elements: a motte – an artificial earth mound crowned by a wooden or stone keep – and one or more baileys, which were fortified courtyard-style enclosures built beside the motte. The motte provided a commanding view of the surrounding landscape and served as a final refuge if the outer defenses were breached, while the bailey housed soldiers, servants, livestock, and supplies necessary for withstanding a siege.

The Norman conquest of England famously spread this castle design across Britain in the 11th century, but the architectural form originated in northern France, particularly in Normandy and Anjou, before spreading throughout Europe. Switzerland, positioned at the crossroads of medieval European powers, adopted these defensive structures as local lords sought to protect their lands and assert their authority. The newly discovered castle at Tbeli fits perfectly within this pattern of early medieval fortification, representing the efforts of regional nobility to create defendable strongholds during a turbulent period of European history.

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Preserving the Past for Future Generations

In a decision that may disappoint those eager to see excavations begin, the Thurgau Office of Archaeology has announced that it will not be conducting archaeological digs on the newly discovered castle plateaus. Instead, the agency has chosen to leave all structures and artifacts in the ground, preserving them for future research when more advanced archaeological techniques may be available. This approach reflects growing archaeological practice that recognizes the destructive nature of excavation – once a site is dug, its original context is lost forever. By protecting the site now, archaeologists ensure that future generations with more sophisticated dating methods, preservation techniques, and analytical tools will be able to extract even more information from these precious remains.

The artifacts already recovered—the pottery shards, iron objects, and medieval arrowheads—are currently undergoing conservation and will be studied in detail to provide insights into the castle’s construction date, the daily lives of its inhabitants, and the circumstances of its destruction. These objects serve as tangible connections to the men and women who lived, worked, and fought at this forgotten fortress nearly a millennium ago. The discovery adds another piece to the complex puzzle of medieval Switzerland and demonstrates how modern technology continues to reveal secrets hidden in plain sight within our landscapes.

Top image: Digital artistic impression of the castle detected by Lidar Uesslingen-Buch in northeastern Switzerland. Source: Thurgau Cantonal Archaeology Office

By Gary Manners