Rubuta ci gaba don wannan sakin layi - Mint da aka yi aiki a Kluczbork a lokacin mulkin Duke Bolesław III Mai karimci, a farkon karni na 14. A cikin 1426 Duke Louis II na Brzeg ya ba Kluczbork gata na kasuwar gishiri. Mutanen da suke yaren Polan ne suka fi yawa a birnin har ƙarnuka da yawa. Masana'antun masana'antu sun fara girma a cikin muhimmancin 1553, amma sun sha wahala a wuta a 1569. Wata babbar gobara ta halaka gidaje da yawa a ranar 8 ga Disamba, 1562. Ranar 25 ga Janairu, 1588, kwana ɗaya bayan Yaƙin Byczyna
, Sojojin Poland a karkashin Jan Zamoyski sun wawushe garin. Mutanen garin sun amince da Furotesta a shekara ta 1656 kuma suka canja Cocin Roman Katolika na yankin zuwa Cocin Lutheran. 'Yan'uwan Poland sun zauna a cikin birni bayan 1660, kuma sun shirya majalisunsu a cikin birni a 1663 da 1668. Garin yana da mazaunan kusan 1,000 a cikin 1681.