Hermann Oppenheim (1858-1919) was a German neurologist without an academic career, who in his productive period around 1900 made a name for himself during his lifetime as a major player in the history of German neurology with his many contributions to multiple sclerosis, syphilis and the controversial study of traumatic neurosis; however, it is almost unknown that in 1890 he introduced the term "witzelsucht", which is still used internationally today. Moritz Jastrowitz dealt with behavioral abnormalities due to frontal brain injuries 1 year earlier and used the term "moria" for a form of mental disorder associated with a kind of childish behavior and inappropriate jocularity. Oppenheim was critical of this and differentiated his "witzelsucht" from this. With this term he wanted to describe humoristic feeble-mindedness in a much narrower sense, which stands in striking contrast to the usual symptoms in cases of cerebral tumors. Oppenheim recognized the frontal brain, particularly the right brain, to be an important functional unit for humorous behavior. Modern research has confirmed that the processing of humor requires a complex interaction of multiple brain regions. Damage to the right frontal lobe or to connecting structures can lead to the disorder "witzelsucht". Whether a simultaneous damage to the left hemisphere must be present or if this is dependent on the individual dominant hemisphere, needs further research.