Die mittelalterliche Glockengussgrube in Dülmen

More than 1,000 years ago, the sound of church bells began to determine the lives of people in Europe. Bells rang for prayer, warned of danger, or conveyed messages. In the time of the mission of Westphalia, they were also an effective means of demonstrating the victory of Christianity to the outside world. As far as the history of the bells goes, in 2016, during the excavations of a specialist company, accompanied by the LWL Archaeology in the old town of Dülmen, before an intergenerational centre can be built on the site next to St. Victor's Church, archaeologists are on the move. In spite of the wind and weather, they continue to penetrate deeper and deeper into the soil of the inner city of Dülmen, and thus further and further into the past of its former inhabitants. For the researchers, the excavation equals the study of a city chronicle. The difference? No pages, but more than 1,000 years old traces, they have to read. This time it is an arrangement of charcoal remains, clay, and red-coloured rolls and sandstones due to heat. Only a few specialists are able to draw the right conclusions from this finding. The excavator Dr. Gerard Jentgens and his team came across the remains of a medieval bell casting pit, an extremely rare find. This is why the most modern methods are used. The pit is measured with a laser scanner. With the collected data, a highly precise 3D representation is later possible. Only a few can recognize the remains. For the archaeologists, however, it is a real treasure trove. Small bronze balls indicate the material properties of the bell. It consisted of 62% copper, 27% tin, and 11% lead. New and new fragments of the cast mantle appear. Perhaps more than one bell was cast here? Werner Peine, then head of the medieval and modern archaeology at the LWL, is informed about the progress of the new excavations. And then we have parts of the bell itself, this is a piece of mantle. In the bell casting pit, we already expected to find some fragments of the mantle and the core. But that we were able to find such a large number of fragments there, surprised us. This alone indicates that several bells were cast there. Each single fragment is captured with the laser scanner and duplicated as a copy in the 3D printer. Also in terms of color, all pieces are compared to the original by hand. The goal is to reconstruct the cast mantle of the bell, and thus also its shape. For display purposes, the archaeologists have recreated a bell core. Bell casting was a complicated process. Back then, as it is today, it is only mastered by a few specialists. The cast form for an early medieval bell basically consists of three parts. On the one hand, there is the core, which we have reconstructed here. A thin layer of wax follows, and then on the outside again a clay mantle, the outer form mantle. The wax is later melted between these two parts of the form and then replaced by the cast by the bronze mantle. Notable is the size of the form core, which gives an idea of how large the bronze bell was. With a diameter of 90 cm for our excavation site here, this is already a huge measure for an early medieval bell. Finally, the pit reveals a new secret. When further excavation is carried out, the excavators are pushed a little deeper into a further firing channel with charcoal remains. This older system was apparently simply overbuilt after its use, to then put the younger one into operation. The structure and function can still be understood today. I am now kneeling in the bell casting pit, which was originally about 1.5 meters deep. Here, in the middle of the bell casting pit, the bell cast form was placed on these four stones. Here the bell form was burned by a huge fire that was ignited below the form. The fire was supplied with wood and oxygen through the heating channel, which extends here. But when were the two pits fired? This is to be clarified with the help of charcoal remains. Based on the state of decay of the carbon isotope C14, which is contained in the samples, the find can be dated. The archiving and duplication of the bell form parts was worthwhile. With their help, Gerard Jenkens gains amazing information again. The two casting systems that were exposed have shown that in both cases quite large, very large bells were cast, with radii of 45 centimeters. This corresponds to a diameter of 90 centimeters. We also have corresponding form coat pieces that fit very nicely to this radius in the found material. This example can also be applied to this radius template. But, and that was particularly exciting for us, there are also pieces with much smaller radii. Here, that's about 20 centimeters, that corresponds to a bell with a diameter of 40 centimeters. In Dülmen, not only two large bells were cast, but also at least one smaller one. Ceramic finds had already enabled an order in the Karolingian period. The results of the charcoal examinations are still a sensation. The date is between 670 and 775 AD. A result that gives the find European significance. The bell casting pit of Dülmen is thus the oldest ever found on our continent. In addition, the outstanding find provides new insights into the settlement history of Dülmen and the early phase of the Saxon mission in Westphalia.