In the second half of the 14th century Opoczno prospered, and in the 1360s, it was named the capital of a newly created county, which meant that it was no longer subjected to the Castellany of Żarnów.
În a doua jumătate a secolului al XIV-lea Opoczno a prosperat, iar în anii 1360 a fost numit capitala unui Județ nou creat, ceea ce însemna că nu mai era supus Castellany⁠(en) Żarnów⁠(en).