 These are listed in the following table, in descending order of population.The history of Opoczno County dates back to the Middle Ages, when its present territory was divided between the castellanies of Skrzynno and Zarnow.By early 14th century, Opoczno emerged as the most important urban center of the region, and when castellanies were replaced by counties, the Opoczno County ruled by a starosta was created some time between 1346 – 1368.