Milko Kos neither dealt specifically with the counts of Celje/Cilli from the scientific point of view nor he wrote any exhaustive monography about the development of that feudal family in the Slovene ethnic territory, however, he has contributed more interesting views dealing with their development and has also helped to clear up their significance and role in the Slovene history. And these views are exactly what the author points at in his study, critically estimating some viewpoints of Milko Kos at the same time.