So in my opinion, only an architect can broke in to secure place like the library,after he checked the blueprints of the building. Without the knowledge of an arhitect there is no chance to broke in to the Library and stole something unnoticed. This is why he only takes the "riskiest and trickiest tasks". He know he can do it, so he can earn a lot of money.
My account name is Jozsikahh now playing on 5x server: https://ts29.travian.com/dorf1.php
My email address is: firstname.lastname@example.org