the lowest rank in old times was the freiherr or sword nobility that came allways from a knight but after 1400 another class of nobility was born - the patent nobility. most times you had here a high ranking official that got a nobility patent for special merits in the country.
its clear that the descendant of a real knight dont see himself on the same rank like the descendant of a high ranking clerk.

https://de.wikipedia.org/wiki/Rangkrone