„Als der algoriſmus ſpricht…” – Indisch-arabische Zahlen und der Algorismus in der Geometria Culmensis

Abstract

The Geometria Culmensis was written around 1400 and is one of the first known mathematical treatises in German. A textbook on land surveying, it not only uses the Hindu-Arabic numerals throughout the text but also frequently refers to the most influential treatise on these new numbers, the Algorism. Roughly a hundred years before the first German arithmetic books, the Geometria Culmensis tries to educate laymen on the techniques found in the Algorism. This leads to some pertinent questions: How early did the Hindu-Arabic numerals spread through the vernacular milieu in German-speaking countries? How important was a mathematical education outside of a scholarly environment (the text refers to the necessity of teaching laymen how to measure and calculate correctly)? What does this early German mathematical language look like, knowing that the author of the Geometria Culmensis had no template from which to copy?