After leaving Hanover for a time, to tour Germany, he enrolled at the Grand-Ducal Saxon Art School, Weimar in 1872.
[1] In order to gain further inspiration, he travelled frequently; visiting Emsland, the Teutoburg Forest, the Lüneburg Heath and the Südheide (now a nature park).
During this time, he was offered a professorship at the Kunstakademie Königsberg, but he declined because he wanted to remain in his homeland.
Together with the painters Hermann Schaper, Oscar Wichtendahl [de] and Ernst Pasqual Jordan, he decorated the singer's home, known as the "Salle Nollet".
[3] In 2004, the Historisches Museum Hannover presented a retrospective of works by every member of the Koken family.