Let’s start the week with this (probably pre-war) picture of Austro-Hungarian soldiers. I’ve been puzzled by the presence of the numbers written by an anonymous hand on each of them. Usually, such numbers were written in order to help to identify the portrayed men, with a numbered list written on the back of the document. But in this case, several of them have the very same number (#100, #54 or #3).
My opinion is that this number indicated in which regiment served these men. If this can help to know more, here’s the back of the picture with all their names!