Jul 6 2018

A Romanesque Bell for a Romanesque Chapel

Bastian Asmus

Visiting the amazing bell foundry Grassmayr in Innsbruck, Austria, which houses the Romanesque bell from Hachen.

A Romanesque bell for the Romanesque Bartholomew chapel! What a fantastic development based on experimental archaeology! After working since 2015 on the reconstruction of the bell casting technique described by Theophilus Presbyter , which finally led to the long-awaited bell for the Campus Galli  earlier this year, there is another step to be made: For not only does the metropolitan chapter of Paderborn want the public to experience how a Romanesque bell was cast around the year 1000, no, this bell is to be installed in the Romanesque Bartholomew Chapel, which celebrated its 1000th anniversary in 2017.

The Bartholomew Chapel is not just any Romanesque chapel, it is an important architectural achievement of the high Middle Ages, which with its Byzantine style elements has no direct precursors or subsequent buildings. This oldest hall church in Germany was built in the Ottonian period as a palatine chapel during the construction of the new Paderborn palatine.

Bartholomäuskapelle, der Dachreiter für die romanische Kapelle ist noch leer!

The Bartholomew chapel in Paderborn, dated to the early 11th century. The ridge turret is still empty! There the new Romanesque bell will be installed.

A Romanesque bell in the making

The St. Bartholomew’s Chapel is given a bell that matches its date of origin. As a model for the new bell, a Romanesque bell from North Rhine-Westphalia was chosen. The bell of Hachen can be admired today in the bell museum of the bell foundry Grassmayr in Innsbruck, which acquired the bell in 1938 from the bell foundry Heinrich Hupert from Brilon. The Grassmayr brothers allowed me to measure the bell exactly, so that a new creation of this bell type can succeed. This is not about making an exact copy of the Hachen bell. Rather, it can be seen as a model for casting a “new Romanesque” bell. The technology of bell casting is similar to that used to make the Canino bell, i.e. the lost wax process as described in Theophilus Presbyter.


Romanesque bell from Hachen, Germany

The Romanesque bell from Hachen is housed in the bell museum Grassmayr in Innsbruck. In comparison to the much older Canino bell, this bell exhibits a much more pronounced waste and shoulder section.

By 1017, the church had already had at least two centuries of experience in the casting of bells. In addition to increased wall thickness of the rib the shape has also developed from an egg-shape to a more pronounced waist and shoulders. Also the sound holes are often only present as a typological rudiment. Next to the technical casting questions, here are a few questions concerning the conceptual side of bell development:

  • can the different dimensions of the bell be put in a certain ratio?
  • how was a bell designed in the Middle Ages?
  • what were the measurement options?
  • how exactly can the sound be predicted?

All ribs of contemporary bells were studied and compared. Drescher has already done very valuable work here , and many of the ideas presented here have their basis in his work.

Digression: The fingerprints of the Hachen bell founder

During the examination of the Hachen bell I discovered the fingerprints of my colleague who left them in the bell model a 1000 years ago. Even for an archaeologist this was an extremely impressive moment. It also goes to show the surface quality the casting method was capable to produce.

1000 year old fingerprints on Romanesque bell detected.

A 1000 years old fingerprints of my “colleague” in the handle of the Romanesque bell from Hachen! Width of the handle shown: 33mm.

Still no strickle board in the Romanesque period

How can we imagine the manufacturing process? Has a cleric seen another bell and developed a desire to also possess a bell? Was this wish expressed like: “I would like a bell like the one from Mainz” or was it completely different? I don’t think I can answer those questions that quickly. But since Theophilus still does not speak of the use of a strickle board a hundred years later, we must assume that the ribs of the bells were made in a different way. A direct comparison of different ribs was therefore not possible in the medieval period. This would explain also explain why the sound finding of the early bells had to be based on chance at first. It is assumed here that only the documentation of the bell rib may have led to controlled experiments on the influence of the rib on the sound.

The production of the Romanesque bell for Paderborn poses a similar problem for me. I have a client who knows a bell he’d like to have. I can look at the bell and measure it, but I cannot use the strickle board to to transfer the rib, as this was unknown in the 11th century. I can transfer the dimensions recorded with the gripping compass with the gripping compass. This inevitably results in inaccuracies which, however I suspect were not a problem then. Nevertheless, during working at the bell you wonder whether there were any underlying rules to lay out the measures. Drescher proposed that the diameter of the sound  bow provided a base measure, from which the rest of the bell may have been constructed.

The Hachen bell has a height to sound bow ratio of 5:4, as well as a ratio of the diameter at the shoulder to the total height of the bell 1:2, and a ratio of about 1:1 strike ring diameter to the height of the sounding body. Further clear ratios could not be determined so far, in particular to the curvature of the bell waist.


The project is documented as a video log and recorded in several short films. So far, the first four working days have been completed. Note that working days are not the same as the process days, as the relatively massive casting core takes several days to dry. So far, the process has been ongoing since June 23, 2018, so that eleven process days have already passed by the time this article is written (July 3, 2018)


Day 1 and 2 Romanesque bell – setting up shop and making of the core

Day 3 and 4 Romanesque bell . finishing the core

Day 5 and 6 Romanesque bell – making of wax model

Day 7 to 10 Romansque bell – finishing the wax model

Tag 11 bis 15 Romansque bell – mould, pit and furnace



Jan 20 2018

Handgonne breech loader, cast bronze Part I

Bastian Asmus

In this series of articles I will find out how to make a particular handgonne, and in extension, very early firearms in general; or rather how they could have been manufactured with the contemporary technology. I am not much for guns’n shooting, but I have always been intrigued by the casting process of guns and cannon.
Why? Because, as a fully trained bronze founder I know that there are a lot of challenges involved and even a lot of room for failure. As a professional maker of things, failures are among the least favourite topics to talk about. However, also being a scientist helps to overcome this predicament: Without failure there can be no progress. Or in other words we should not content ourselves with our hypotheses, but should constantly try to falsify them.


Early breech loaded handgonne.

This image of a supposedly 15th century handgonne shows a very early breech loading system, that did not take hold for centuries to come. Technical limitations in the manufacturing process, may well be responsible for this. It could simply not be manufactured as easily as the much more common muzzle loaders. Source: Viking Swords Forum thread 7364.

Continue reading

Oct 6 2017

Film: How to make a 15th century beer tap

Bastian Asmus

Reconstruction: Functional tap from the early 15th century. Reconstruction: Early 15th century tap. The location is Zurich, Switzerland.

Some time ago I made a tap for a re-enactment brewer. I was already able to gain experience with the production of tap taps when I made my Aquamaniles. Therefore I decided to document the manufacturing process. Medieval taps often have a stylized cocks as a handle on the plug.  From the end of the Middle Ages taps or spigozs were made by the Zapfenmacher. One of the centres was Nuremberg. In the iamges of the Mendelsche and Landauersche Hausbücher of the Zwölfbrüderstiftungen it is interesting to note that the process step for the production of the taps shows only the reworking, but never the moulding. The illustration of the redsmith by Jost Amann in Hans Sachs book of trades gives at least a hint of the moulding material..

In the background, lumps of clay may have served as a raw material for the moulding material.

A little later again, in the 17th century, Christoph Weigel depicts the Zapfenmacher in its own right . Here a strong specialisation had taken place within a century.

The films are not about a strict archaeological experiment. Rather, it is a matter of examining some hypotheses on the manufacturing process. First and foremost, these were:

  1. Is it possible to make a wax model where plug and tap fit snugly?
  2. Can you cast this in such a way that there is little rework?
  3. How can the grinding of the plug into the tap be mastered manually?

Have fun watching. As always, I am looking forward to your criticism, questions or suggestions.

The first part deals with the history of the tap and the production of the wax model.

The second part is about moulding the wax model, pouring the tap and the first cleaning after casting.

The third part is about finishing the cast tap. This means that it must be roughed, filed, drilled and ground. The grinding of the plug into the tap’s body was particularly exciting. In fact, absolutely leak-proof tap can be produced with the simplest of means.