Were there ever any literal robber barons?

by ac240v

As in, not industrialists but actual medieval nobles who lived by robbing people?

If not, where does the expression actually come from?

Edit: I'm asking mostly because it's difficult to imagine how such a noble wouldn't be dealt with in a fairly short order by his neighbours, if nobody else...

Assorted_Bits

Even though more can be said about it, this answer by /u/A_Soporific goes into the history of the term and describes "real" robber barons.