Mörsburg Castle

Mörsburg occupies a southern spur of a ridge at roughly 511 metres above sea level, overlooking the Thurtal valley. The site commands clear sightlines toward Kyburg, about nine kilometres away, and Hegi Castle at roughly three kilometres, and an old route toward Pfyn and Lake Constance once ran nearby. The surviving complex centers on a large square keep and is surrounded by defensive walls that once enclosed terraces with domestic and economic buildings.

The primary keep has a square footprint of roughly 16 by 16 metres. Its original masonry was relatively slim, with walls about 1.30 metres thick; later strengthening increased wall thickness to nearly five metres. Around the tower the Kyburgs added a U-shaped outer casing built from large glacial boulders set into heavy masonry, the casing opening to the southeast toward the garden. The outer face of that erratic masonry begins about two metres above present ground level, which indicates that an earlier earthen fill around the lower walls was later removed.

A surrounding defensive wall led from the keep to a residential knight’s house and to a narrow outer enclosure for defence, now serving as the stairwell. Those enclosing works and the forebuilding date to the late twelfth century and predate the large boulder casing around the tower. Eastern and western additions attached to the forebuilding date to about 1300. By the mid-thirteenth century a ring wall enclosed two south-eastern terraces that held several houses and store buildings; excavations uncovered buried foundations belonging to those structures, including evidence for an upper-floor representative hall marked by two robust columns flanking a fireplace.

Vertical alterations from the first half of the thirteenth century changed the tower’s interior. Timber-framed third and fourth storeys were added around 1240 to create the present Great and Small Halls. The third storey contains an early Gothic chapel covered by ribbed cross vaults that sits directly on the older wall ring. The chapel’s plan and carved capitals show affinities with buildings in the Savoy and Lake Geneva region, and the interior follows a French–Savoyard model noted in the decorative language of the vaulting and capitals.

Later fittings survive on the upper floors. The fourth floor contains a large banqueting hall dated 1735 and a smaller hall that displays important historic stoves: a complete tower stove dated 1574 by Ludwig Pfau I and a cube-shaped stove by Heinrich Pfau, active in the late sixteenth and seventeenth centuries. In the cellar, which now forms part of the museum, visitors find historic wine barrels and agricultural implements, including a trotting device used for pressing and a large flaxseed press, alongside two old tavern signs.

Archaeological excavations in 1978–79 revealed burnt occupation layers, buried building remains and consolidated wall traces that are now exposed in the southern garden. Further work in 1996 on the outer courtyard uncovered a prehistoric pit, the cellar of a thirteenth-century building, and the remains of a storehouse destroyed by fire around 1300. Many of these features survive in situ or have been consolidated for display, giving a layered picture of the castle’s medieval domestic, economic and defensive fabric.