For years people working in the former St. Katherina Church near Langerwehe had noticed the enigmatic drawings, but it wasn't until 2009 that the LVR regional authority for monument preservation began closely examining their origins, spokeswoman Sabine Cornelius told The Local.
They were surprised to find that the forty-by-two-metre plaster wall bore the tentative marks of young apprentices in the 15th century.
“There are 42 different hammers etched into the wall, and one can clearly see which variety,” Cornelius said.
Among them are stone-cutting, carpentry and slate hammers, in addition to repeated attempts at creating geometric shapes – but no words.
“It is very possible that the young apprentices were using the hammers as a kind of signature because they couldn't write,” Cornelius told The Local.
The apprentices were likely at the nunnery near Aachen during late-Gothic renovations which happened under Abbess Margarete von Fleck between 1492 and 1506. During that time the outer wall disappeared into an attic of a building addition, likely creating an ideal practice canvas.
“These were something spontaneous not meant for posterity, and in this sense it is really particularly appealing,” Cornelius said.
“It's a look into the working conditions back then. You see that some drawings, for instance rosettes, are quite perfect and probably created by the master, and then there are the clumsy attempts at imitation by students.”
According to a statement by the project's lead historian, Dr. Ulrike Heckner, the drawings are an unusually personal and well-preserved testimony from people often overlooked by history.
“Only rarely does historic graffiti from handworkers survive, hence the plaster etchings are an especially precious and unique document of the everyday life and working world in the late Middle Ages,” she said.