Location: Middle Rhein Map
Constructed: 1020 by Otto von Hammerstein
Hammerstein Castle or Burg Hammerstein am Rhein is located on the Eastern bank of the Rhine river in Germany. Very few ruins are left from the magnificent original building. Original fortress of Hammerstein Castle or Burg Hammerstein was build in 1020 by Otto von Hammerstein. In 1071 a new citadel was build here by Henry IV, king of Germany and Holy Roman Emperor. Remains of the 16 feet thick outer wall and the tower are still visible on a 196 meter high hill. Today it is hard to imagine that at certain time this castle was build and occupied by Henry IV who brought here his crown insignia. It served as a private imperial residence. However the castle was heavily damaged in the 17th century during the Thirty Years’ War and soon abandoned thereafter. Only a corner tower with few sectors of the wall are visible from the river. If you have time you can climb the steep hill side to reach military fortifications. Some of the locals reported finding small artefacts from centuries of castle occupation.
Burg Hammerstein (also known as Hammerstein Castle or Burg
Hammerstein am Rhein) is the ruin of a medieval hilltop castle
(Höhenburg) perched on a steep basalt spur at about 195 meters above sea
level on the east bank of the Rhine River, just south of the village of
Hammerstein in the Neuwied district of Rhineland-Palatinate, Germany. It
is widely recognized as the oldest verifiable castle complex in the
entire Middle Rhine Valley.
Today, only fragmented ruins remain—most
notably a prominent round tower (often called the Mühlenturm or
Zollturm, or “windmill tower/toll tower”) and sections of enclosure
walls—accessible via the Rheinsteig hiking trail and a short path from
the village. The site offers sweeping views over the Rhine, but the
structure itself is a stark reminder of centuries of conflict, imperial
intrigue, and deliberate destruction.
Origins and Construction
(10th Century)
The castle was constructed around 900–1000 CE by the
Conradine (Konradiner) dynasty, a powerful Frankish noble family that
played a major role in the early Holy Roman Empire. It was first
documented as an imperial castle (Reichsburg) around 1000–1002. Some
early theories proposed a possible Roman origin due to the distinctive
“fill-wall” masonry technique in the enclosure walls (a method known
from Roman engineering), but modern scholarship dates it firmly to the
10th century.
Strategically located to control river traffic and the
surrounding Engersgau region, it quickly became one of the most
important fortifications along the Rhine. The villages of
Niederhammerstein and Oberhammerstein grew up under its protection in
the following centuries.
The Otto von Hammerstein Affair and the
1020 Siege (Early 11th Century)
The castle’s most famous episode
centers on Otto von Hammerstein (c. 975–1036), Count of Engersgau and
the first well-documented burgrave (castellan). Otto married his distant
relative Irmingard (Ermengarde) von Verdun (daughter of Godfrey the
Captive, Count of Verdun). The union was challenged on grounds of
consanguinity (blood relation, cited variably as fourth or seventh
degree) by Archbishop Erkanbald of Mainz, who had political motives to
weaken Otto.
In 1018, Otto defied an imperial and ecclesiastical
order to dissolve the marriage. He attacked the archbishop’s entourage,
captured several men, and held them hostage inside the castle. Emperor
Henry II responded with a winter siege in 1020. Despite its reputation
as “impregnable,” the castle surrendered on December 26, 1020, after the
defenders were starved out. Otto and Irmingard handed over both the
hostages and the fortress. The marriage dispute dragged on until 1027,
when the new Emperor Conrad II (himself in a similarly questionable
marriage) allowed the couple to remain together. Their only son, Udo,
predeceased them, and the direct Hammerstein line eventually faded.
The siege left the castle badly damaged and temporarily abandoned.
Restoration and Peak Imperial Importance (11th–14th Centuries)
Emperor Henry IV restored the castle in 1071 and granted the burgraviate
as a hereditary imperial fief to the Hammerstein family. From this point
onward, it served multiple high-level functions:
Storage for
imperial regalia: Both Henry IV (in 1105, while fleeing his rebellious
son Henry V) and Henry V deposited the Holy Roman Empire’s crown jewels,
insignia, and relics here for safekeeping.
Toll and customs station
(Zollburg): From the late 11th century, it collected Rhine river tolls,
a lucrative source of income.
Mint: A mint operated here from 1215,
producing small-denomination coinage (“Kleinen Münze”).
Prison and
refuge: It briefly held high-profile prisoners (including opponents of
Henry IV) and served as a safe haven for the emperor himself.
King William of Holland visited in 1225, and the nearby settlement of
Oberhammerstein received town rights in 1337. The castle remained a
direct imperial holding until 1374, when Emperor Charles IV transferred
feudal oversight and its dependencies to the Electorate of Trier
(Kurfürstentum Trier).
Transition to Trier and Later Medieval
Period (14th–16th Centuries)
After the burgrave line died out around
1417–1419, Trier annexed the fief outright. In 1410, Archbishop Werner
of Trier had a new tower constructed (parts of which are still visible
in the ruins). In 1431, the castle and its valley were pledged to Count
Ruprecht IV von Virneburg, who was authorized to invest 1,500 gulden in
fortifications.
Major repairs occurred in 1576: records note the
installation of 96 new windows and repairs to 30 towers. However, a 1646
etching by Merian shows only seven towers still standing, indicating
gradual decline even before the wars of the 17th century.
Destruction During the Thirty Years’ War (17th Century)
The castle
changed hands repeatedly during the Thirty Years’ War (1618–1648).
Spanish forces occupied it from 1632 to 1646, followed by troops under
Charles IV, Duke of Lorraine (1646–1654), who used it as a base for
raids on the surrounding area. In 1654, combined forces of the
Electorate of Trier and the County of Wied (Grafschaft Wied) recaptured
it after a difficult siege. To prevent it from ever serving as an enemy
stronghold again, the victors deliberately demolished (“geschleift”) the
powerful fortress, razing it almost to its foundations.
This act of
destruction ended its military role forever.
Post-Medieval Fate
and Modern Ownership (18th Century–Present)
After the Napoleonic
Wars, the ruins passed to the Kingdom of Prussia in 1815. The Prussian
fiscal authority sold them in 1823; they changed hands several times in
the 19th century. In 1893, the family association of the Barons
(Freiherren) von Hammerstein purchased the site and has owned it ever
since.
The ruins have remained largely untouched since the
17th-century demolition, though they are stabilized and open to
visitors. The village church at the foot of the rock (with bells cast
around 1050—the oldest on the Middle Rhine) and other local structures
still echo the castle’s long shadow.
Burg Hammerstein (also known as Hammerstein Castle or Burg
Hammerstein am Rhein) is a ruined 10th-century Höhenburg (hilltop
castle) in Rhineland-Palatinate, Germany—the oldest verifiable castle
complex in the entire Middle Rhine Valley. Perched at 195 m elevation on
a steep basalt spur overlooking the Rhine River near the village of
Hammerstein (south of Bad Hönningen, district of Neuwied), its
architecture is a classic early medieval example of a topography-adapted
defensive enclosure designed for river control, imperial oversight, and
storage of the Holy Roman Empire’s regalia (until 1125).
The castle’s
layout conforms tightly to the irregular contours of its rocky
promontory: steeply dropping toward the Rhine on one side and more
gently sloping on the other. It features an elongated, slightly
crescent- or sickle-shaped (leicht sichelförmig) perimeter defined by a
massive ring wall (Ringmauer or Bering) measuring approximately 120 m ×
35 m. This enclosure wall encloses a central core bailey (Kernburg) and
reflects early medieval construction priorities—strategic elevation,
river surveillance, and robust masonry using locally quarried basalt
lava stone.
Ring Wall and Enclosure (Primary Defensive System)
The defining feature is the ring wall, built with small-format
hand-squared basalt blocks (kleinformatige Handquader aus Basaltlava) in
load-bearing masonry. Average thickness is 2–3 m, but sections reach far
greater strength for maximum defense.
Barbarossamauer
(northeastern section): The standout element—a shield-wall-like
(schildmauerartig) fortification up to 4.20 m thick, constructed in a
rubble-stone core with inner cladding of precisely fitted basalt lava
quoins. It includes an internal staircase leading to a wall-walk
(Wehrgang) and features loopholes (Scharte). Rounded corners enhance
structural integrity and defensive coverage. Scholars attribute this
(and parts of the broader ring wall) to the Staufer (Hohenstaufen)
period (12th–13th centuries), though some early infill-masonry
techniques (Füllmauertechnik) once suggested possible Roman origins (now
largely discounted). This thick wall protected against the main landward
approach.
Other ring-wall elements: Rounded corners, remnants of
battlements, and a vanished round tower on the western (most vulnerable)
attack side plus a square watchtower at the southwest corner. The wall
was partially divided internally by a transverse partition (foundations
preserved) when the castle functioned as a Ganerbenburg (jointly held by
co-heirs of the Burgraves of Hammerstein).
Core Bailey and
Residential/Keep Structures
At the heart of the enclosure lies a
large rectangular core building (Kernbau or Palas-like structure),
measuring roughly 20 m × 23.5 m (or 20 × 23.4 m in foundations), with
rounded corners for better resistance to artillery or undermining.
Exterior appearance is tower-like or keep-like (wohnturmartig),
divided internally into multiple rooms suited for residential,
administrative, and storage functions (as an imperial castle).
Masonry: Consistent small hand-squared basalt blocks.
Date: Likely
Salian-period (11th century) foundations, possibly originating in the
late 10th century or rebuilt after the 1020 siege under Emperor Henry
IV. Only sparse wall fragments and foundations survive today; a modern
wooden structure now occupies part of the site.
Attached to the
east side of this core is an 8 m diameter round tower, providing
flanking fire and additional residential/defensive space.
Towers
Two prominent towers define the silhouette:
Zollturm (Toll Tower) /
Mühlenturm (Mill Tower): A powerful, detached round tower standing alone
at the southern/western tip of the rock spur on the Rhine side. Built
around 1410 on orders of the Elector of Trier (Werner von Falkenstein),
it served customs and river-traffic oversight (and possibly milling).
Its isolated position maximized views and control over the Rhine;
substantial ruins remain as a landmark.
The eastern round tower
(mentioned above) integrated with the core building.
Gates and
Access
Primary entrance from the south, secured by a gate Zwinger
(outer defensive courtyard) and a reconstructed gatehouse (Tor). A sally
port/outpost gate (Ausfallpforte) allowed sorties.
The steep terrain
made the southern approach the logical (and fortified) entry point,
reachable today via the Rheinsteig trail (about 20 minutes’ walk from
parking in the village).
Materials, Construction Techniques, and
Evolution
Primary material: Locally quarried basalt and basalt lava,
formed into small, hand-squared ashlar blocks for durability without
extensive mortar in some core sections. Rubble stone fills thicker
walls.
Phases visible in ruins:
10th century (Conradine origins):
Initial enclosure and core.
Post-1020 siege damage and 1071
restoration under Henry IV.
Staufer-era (12th–13th c.): Major
strengthening, including the Barbarossamauer.
1410: Addition of the
Zollturm for late-medieval customs functions.
Later repairs (e.g.,
1576) before deliberate slighting (Schleifung) in 1654 during the Thirty
Years’ War aftermath.
Post-1654 stone-robbing reduced the fabric,
but 1990s restorations stabilized key walls and the gate. No moat
existed (unnecessary on the rocky spur).
Current State and
Architectural Significance
Today Burg Hammerstein survives as an
atmospheric ruin with significant standing masonry—particularly the ring
wall, Barbarossamauer, core foundations, eastern round tower stump, and
the prominent Zollturm. The open, freely accessible site (no entry fee)
offers commanding Rhine views and illustrates the evolution of early
imperial Rhine castles: from simple 10th-century enclosures to fortified
Staufer-era strongholds and later toll stations. Its kidney-shaped plan,
thick shield walls, and topography-hugging design exemplify adaptive
medieval military architecture before the shift to more residential
Renaissance palaces.