Joseph Hartmann

Joseph Hartmann's first-born son, Joseph Theodor Hartmann (*1897), also worked as an art dealer. On 31 March 1930, he married Thea Heinzel, who was born in 1907 in Hanynau in Silesia. According to the population register, he worked in his father's art shop until 1939, after which he was (initially) deployed as a medic in the military hospital I in Wiesbaden. He later became an American prisoner of war, from which he was released on 23 April 1946 and returned to Mainz. The family seems to have had business connections to Cologne from an earlier time.

In May 1931, the following advertisement appeared in Weltkunst:

Following Hartmann's connections to Cologne, the database of the Deutsche Nationalbiobliothek contains a reference to Joseph Hartmann as a partner in the art dealership J. & W. Boisserée in Cologne for the years 1902–1906. It has not yet been possible to verify whether this is the Joseph Hartmann we are looking for here, as the documents are not currently accessible.