A copper clock-face on a metal background.
Photo: Jens Mohr, Skokloster Castle/SHM (CC BY).

A Hellish Device

There are many thousands of objects at Skokloster Castle. One of them is a metal box with a strange dial. It is a Hellish Device, accoording to the first inventory list.

The box was once decorated with painted scrolls and ornaments. It has a handle and a few buttons. It is a time device for a time-bomb. The bomb was supposed to be used in the so-called Torstensson War of 1643-45, a part of the Thirty Years War.

A metal box with a copper clock-face. On the top a leather handle.
Photo: Jens Mohr, Skokloster Castle/SHM (CC BY).

The device is wound up like a clock, with a twelve hour delay. When the time is up, a small wheel turns against a piece of pyrite. The sparks created, will ignite the two powder locks and spurt out flames from the two pipes. The entire box was meant to be hidden in a larger casket containing powder, sulphur, wood-shavings, and other flammable objects.

3D-model: Erik Lernestål, Skokloster Castle/SHM (CC BY).

A Suspect

The time device was found almost by mistake. A man acting suspiciously roamed about in the harbour of Wismar in March 1645. He said that he was a cheese merchant and that his name was Hans Grefft.

The taverns he frequented were the usual watering holes for Swedish sailors and soldiers. Some of them recognised the man. He looked, they thought, very much like a man they knew was in Danish service.

The Swedish General Carl Gustaf Wrangel thought it best to apprehend the man and question him. At the same time, some soldiers were sent to Grefft’s lodgings and ransacked the room. There they found two coffins with flammable material and two time devices.

Under torture Grefft admitted that his aim was to ignite two Swedish men-of-war: the Dragon and Three Lions. It was, so Grefft said, the Habsburg Emperor Ferdinand III who had given him the mission.

General Wrangel reported this to his superior Chancellor Axel Oxenstierna and took one of the time devices for his armoury.

Repairing ships in a bay. Oil painting by Adam Willaerts, 1615. Skokloster Castle/SHM (PDM).

Why Wismar?

Swedish and Danish men-of-war fought a battle outside the Danish island Fehmarn in October 1644. (Red circle on the map.) Sweden devastated the Danish fleet but needed to retreat to winter port for repairs afterwards. They chose the nearest Swedish-controlled port, Wismar. (Red star.)

Image: Detail of a map by Anders Bureus, 17th Century. Skokloster Castle/SHM (PDM).

Grefft Tells All

Grefft was discovered, interrogated, tortured and convicted. But the story does not end there. We know today that torture bring out answers, but not necessarily the true answers.

In his confession Grefft said that a tall, stout man from Lübeck had approached him roughly a month earlier. The man had worn grey, badly sewn clothes, grey hair and grey beard. His resided at The Blue Tower, owned by Jörgen Burchhart. Other accomplices were Heinrich Würger and Thomas Ritter. The latter was the leader, according to Grefft.

Of course, General Wrangel had Ritter, Burchhard and Würger arrested.

Hans Grefft was burned alive at the stake.

Torture. Etching by an unknown artist with the initials L.M. Image: Wellcome Collection (PDM).

Why War?

Sweden and Denmark went to war against each other five times in the 17th Century. To understand why, one has to understand Sweden’s geographical challenges at the time.

In 1645 Denmark was considerably more influential than Sweden. Denmark included present-day Norway, Jämtland, Härjedalen, Gotland, Blekinge, Halland and Skåne. The strategic advantages were great. They controlled the entire south part of the Baltic Sea and the Öresund strait. Sweden’s aim in going to war against Denmark was to gain access to the North Sea and the Atlantic.

Image: The rough outlines of the Danish-Swedish border. Skokloster Castle/SHM (PDM).