There are many example of fantasists and con artists creating fake back stories for themselves. Casanova and Cagliostro are among the most famous examples. Affecting fake noble titles was a favourite ploy.
In Germany the Captain of Köpenick is famous to this day as every child at one point reads Zuckmayers play based on this real story. In 1906 a shoemaker dressed up as a captain of the Prussian army, gathered some soldiers under his command, arrested the major and stole money from the city of Köpenick. He was arrested and served a sentence but became a folk hero and was pardoned by the Kaiser. (1) A striking parallel is the confident use of clothes and signs of authority.
(1) https://en.m.wikipedia.org/wiki/Wilhelm_Voigt