Burg Sonnenberg: A Medieval Castle Ruin in Wiesbaden, Germany
Visitor Information
Google Rating: 4
Popularity: Low
Country: Germany
Civilization: Medieval European
Site type: Military
Remains: Castle
History
Burg Sonnenberg is a castle ruin situated in the municipality of Wiesbaden, Germany. It was constructed by the counts of Nassau around the year 1200 to safeguard the town of Wiesbaden and to serve as a military stronghold during territorial conflicts with the neighboring lords of Eppstein.
The origins of Nassau influence in the area trace back to the mid-12th century when Emperor Frederick I Barbarossa likely granted the Nassau family control over the Königshof Wiesbaden as recognition for their support in his campaigns in Italy. The Königshof itself had been referenced as early as 829 as the administrative center of a Carolingian district founded by Charlemagne. Although the lands around the castle originally belonged to the chapter of Mainz Cathedral, the Nassau brothers Heinrich II and Ruprecht initiated construction of the fortress before formally acquiring the property. By 1221, they acknowledged that their occupation of the “Castrum Sunneberc” had been an unauthorized seizure; subsequently, they purchased the land and held the castle as a fief under the Archbishopric of Mainz.
After Ruprecht joined the Teutonic Order in 1230, Heinrich II governed the castle alone. In 1255, the Nassau family divided into two lines, Walram and Otto, with Sonnenberg and Wiesbaden becoming possessions of the Walram line. Before 1283, the castle suffered heavy damage during ongoing disputes with the Eppstein family. Adolf of Nassau, a later German king and son of Walram, undertook significant rebuilding and expansion efforts following this destruction.
After Adolf’s death in 1298, the Eppstein family and Archbishop Gerhard II of Mainz managed to retake the castle, inflicting severe damage during the siege. As a youth, Adolf’s son Gerlach I escaped this conquest. Later in his life, Gerlach I reconciled with former adversaries and launched major expansions that brought the castle to its architectural and strategic peak. The castle’s prominence was highlighted by a visit in 1338 from Emperor Ludwig the Bavarian.
In 1351, under the influence of Count Gerlach’s second wife, Irmengard of Hohenlohe-Weikersheim, the castle’s surrounding settlement was granted town rights by King Charles IV. This legal status included its own jurisdiction. The castle compound was enlarged to incorporate the houses at its base, which were enclosed within a protective wall, and the entire valley area was fortified.
Following Gerlach’s death in 1361, his son Ruprecht inherited the newly established county of Nassau-Sonnenberg. Known as the last traveling knight, Ruprecht engaged in multiple feuds related to his wife Anna of Nassau-Hadamar’s claims. In 1365, he designated the castle as a widow’s residence for Anna. Ruprecht eventually retired from combat in 1384 during the founding of a chapel altar and died childless in 1390.
In 1391, a co-ownership arrangement emerged when Count Diether VIII of Katzenelnbogen, who had married Anna, joined as co-lord. After Anna’s passing in 1405, the castle’s lordship was divided between the counts of Idstein and Weilburg. Over the next two centuries, Burg Sonnenberg gradually fell into decline and partial ruin.
Between 1558 and 1566, Count Philipp of Nassau-Idstein temporarily restored the castle as his residence but died without heirs. By the late 16th century, the fortress was no longer inhabited. During the brutal Thirty Years’ War (1618–1648), the ruined castle provided shelter to roving soldier bands. In the aftermath, local residents quarried stone from the castle walls to rebuild houses in the valley, accelerating its decay into a ruin.
In the 19th century, the picturesque ruins became a favored destination for guests visiting the spa town of Wiesbaden. The city officially acquired the site in 1875. Post-World War II efforts saw the restoration of the castle’s keep. Between 2005 and 2015, the ruin underwent extensive preservation work accompanied by archaeological excavations. Most recently, in 2021, the German federal government contributed €400,000 toward continued restoration following a parliamentary funding request.
Remains
Burg Sonnenberg occupies a rocky spur overlooking the village below, embodying the typical layout of a medieval spur castle designed for both defense and residence. Its earliest section, the bergfried or main keep, was completed around 1208, constructed as a tall stone tower that served as a final stronghold and lookout point.
Between 1221 and 1242, the castle’s upper area was expanded to accommodate growing defensive and residential needs. After suffering severe destruction during conflicts in 1283 and 1298, the castle was not only rebuilt but also enlarged. This included the creation of a lower castle area, expanding the defensive perimeter and allowing space for additional buildings.
A significant architectural development came in 1351 when the castle was granted town rights. As a result, the valley below was fortified, and the houses situated at the castle’s foot were enclosed within a protective defensive wall, effectively integrating the settlement into the castle complex. This arrangement formed a small fortified town under the castle’s protection.
Within the lower castle’s walls, a chapel was constructed in 1384 inside one of the wall towers. This religious building served as a spiritual center for the castle inhabitants and likely functioned as a place of worship for the attached community.
Today, the site retains three known entrances: the original main gate on the eastern side and two former gates leading into the fortified valley area. The bergfried, having undergone restoration after the Second World War, now houses a small museum. Visitors from the castle keep’s viewing platform can look out over the castle grounds and the village of Sonnenberg below.
The ruins have also hosted annual cultural events held in front of the chapel tower on the lower castle grounds, reinforcing the layered social uses the site has maintained through time. Notably, the upper castle was home to a high-end gastronomy establishment until its closure in 2019, pending completion of ongoing restoration work. The site remains accessible, benefitting from the archaeological and structural conservation undertaken from 2005 to 2015, which helped stabilize the ruins and revealed details of its medieval construction.
