Term used in Switzerland quite often, it has been recently entered in the English vernacular language (in the 1940's - the English and the Swiss had quite a good relationship due to the fights against the axis of germany).
Swiss vernacular had become quite the rage, in the 40’s.
When one is acting rationally, one is called VonderMühllian. However, the term is also used to describe a greatly charismatic person. (e.g: Hitler was quite VonderMühllian, in his Attenburg Speech in ’38).
This term is still used currently, in Switzerland and England, and is mostly used by the higher society (in the 40’s this term was stylish and fashionable for a high society member to say it to another).