Altenburg

Altenburg near Märstetten in the canton of Thurgau is a ruined medieval castle in north-eastern Switzerland, not far from Lake Constance. It stands in the municipality of Märstetten on the slopes of the Ottenberg and counts among the more interesting archaeological sites in the canton. Do not confuse it with the city of Altenburg in Thuringia, Germany: this is a small ruin in a Swiss village.

What is this place?

Altenburg is what remains of a fortified hilltop for which no written records survive. Nobody knows who built it or exactly when. Excavated finds show, however, that the mound was in use by the end of the 8th or the start of the 9th century. Around 930, in the time of Hungarian raids, builders added a ditch, a gatehouse, a curtain wall and a wall-walk. Between 950 and 1050 a stone residential building and a tower followed. The tower had to be rebuilt in the 11th century because it stood above a ravine and began to suffer structural damage.

Who ruled here?

The lords of Klingen are associated with its construction. Until 1396 they exercised low justice in Märstetten and Illhart. Around 1155 the cathedral chapter of Constance granted them Märstetten as a fief. Around 1200 the family left the old seat and built a new one. That later castle, Schloss Altenklingen, lies about 600 metres away and was bought in 1586 by Leonhard Zollikofer of St. Gallen.

What will you see?

The ruin was partly excavated between 1901 and 1910. Afterwards the freestanding walls began to crumble, so the cantonal archaeology office restored and reconstructed sections of them. Expect traces of the defences on the hill, rebuilt wall stretches and a wooded setting. It suits visitors who enjoy reading a landscape and its history, not those looking for a complete castle with furnished rooms. The site sits at roughly 47.601 N, 9.086 E.

How to plan a visit

Combine the ruin with a walk around Märstetten. Schloss Altenklingen is close by, and a 2023 monograph by Iris Hutter in the series "Archäologie im Thurgau" compares Altenburg, Burg Klingen and Altenklingen. It is worth a look beforehand if medieval defensive architecture interests you. Wear sturdy shoes: the terrain is forested and uneven.

Frequently asked questions

Is Altenburg at Märstetten a castle with a roof and interiors? No. It is a ruin with partly reconstructed walls and no interiors to tour.

Who built Altenburg? Written sources are silent. The lords of Klingen are associated with it, and archaeology dates use of the hill to around the 8th to 9th century.

Is Altenburg the same as Schloss Altenklingen? No. Altenklingen is a late Renaissance castle from the late 16th century about 600 metres away. Altenburg is far older.

Are there other places called Altenburg? The name is common in German-speaking countries. This text covers only the ruin in the municipality of Märstetten, Thurgau.