He was the son of Wilhelm August Heisenberg (1831–1912), a locksmith (blacksmith) in and from Osnabrück,[1] and Anna Maria Unnewehr (1835–1919).
[2] Heisenberg attended the public school and the council gymnasium in Osnabrück and studied philosophy and other subjects in Marburg from 1888 and from 1889 in Munich, where he turned to classical philology and especially medieval Greek under the influence of Karl Krumbacher.
In 1893 he became an assistant at the grammar school in Landau in der Pfalz (at that time part of Bavaria) and from 1893 he was at the Maximilians-Gymnasium in Munich.
In 1901 he habilitated in Medieval and Modern Greek philology in Würzburg, where he taught from 1908 as an honorary professor in addition to his work as a high school teacher.
She aspired to a university career, correcting tests and even learning Russian to support him in his scientific work.