Archaeologists uncover larger medieval fortress at Zurich’s Hardturm

Archaeologists have discovered a moat and sections of a surrounding wall at Zurich’s medieval Hardturm, showing that the tower was part of a larger fortress complex. SRF reported that the findings emerged during excavations carried out while the city replaced a water pipeline along Fischerweg.

The Hardturm stands between a modern railway bridge and apartment blocks in Zurich-West, beside the Limmat. The tower dates probably from the 12th century, with confirmed evidence from the 13th century, and is one of the last witnesses to Zurich’s High Middle Ages. It is now used as a home.

Researchers had previously assumed that the Hardturm stood alone as a defensive tower. They instead found a wide moat and a ring wall, indicating that it was a lowland fortress with a bridge over the Limmat.

“We now have clear proof: there was a castle with a moat and a wall all around it,” said Manuel Zürcher, an archaeologist who has worked for Zurich’s municipal archaeology department for 15 years. He said the complex must also have contained other buildings for housing, storage, stables and craftwork.

The excavation covers an area about 10 metres long and reaches three metres below ground. Archaeologists plan to continue investigating the interior of the complex in the coming weeks in the hope of finding more evidence of its buildings and daily life.

Stephan Wyss, head of the municipal archaeology department, said the discovery showed how important the location was in the Middle Ages. The Limmat is shallow at this point and has an island, making it suitable for a river crossing.

Traffic and trade were probably monitored there, and tolls may also have been collected. The tower also had a military role and represented the city’s defensive strength, Wyss said.

The exposed wall will either be covered again or removed after the excavations, according to the city’s archaeology department.

The discovery will significantly expand knowledge of the Hardturm’s history, Wyss said. He added that much of Zurich’s history, including that of its neighbourhoods and fortresses, remains beneath the ground and has yet to be fully documented and shared through tours or exhibitions.