The article treats the library of the Smlednik Castle that is described in the catalogue from the year 1771. Almost all important works of the main thinkers of the Enlightment period make part of the existing fund of books. On the basis of detailed analysis it establishes that the owner of the castle Franc Smledniški (Flödnigg) was deeply interested in this movement and was, moreover, a very well read and broad-minded intellectual. These new facts somewhat change the picture of ancient nobility in our territory.