Medieval philosophy
Koeber came to teach in Japan in June 1893, based on the recommendations of his friend Karl Robert Eduard von Hartmann, who overcame his worries about the long sea voyage, earthquakes and having enough English language ability to lecture. He was 45 years old. He studied and worked for 21 years at the Tokyo Imperial University from 1893 to 1914 teaching philosophy, in particular, Greek philosophy, Medieval philosophy and Aesthetics.