Großherzoglich-Sächsische Kunstschule Weimar
Rettelbusch was the eighth child born to a family of innkeepers. After attending the local schools, he went to the Weimar Saxon-Grand Ducal Art School in 1878. Theodor Hagen and Alexander Struys were among his teachers. After trying several styles, he decided to devote himself to landscape painting. Before graduating, however, he had to quit school for financial reasons. In 1880 and 1881, he took lessons to pass the drawing teacher exams with Karl Gussow at the Prussian Academy of Arts.