The area has been populated at least since the 1st century BC. The earliest mention of the town itself is in the 12th century Chronica Boëmorum by Cosmas of Prague. He mentions the town of Cladzco as belonging to the Bohemian nobleman Slavník in 981, father of Bishop Adalbert of Prague and progenitor of the Slavník dynasty.
Bohemian-Polish Borderland
Held by the Přemyslid dukes of Bohemia, the town was also claimed by the Polish kings, which led to a series of armed conflicts: King Bolesław I Chrobry campaigned Kladsko in 1003, but soon after was expelled by Emperor Henry II. In 1080 the Polish duke Władysław I Herman married Judith Přemyslid, daughter of the Bohemian duke Bretislav I and their son, the warlike Duke Bolesław III Wrymouth claimed Kladsko as the dowry of his mother. In turn the Bohemian prince Soběslav I campaigned Kladsko and burnt the town to the ground, but rebuilt it shortly afterwards. He also rebuilt and strengthened the castle located on a high rock overlooking the town.
A region of Bohemia
In 1137 by the agency of Emperor Lothair III of Supplinburg the rivals finally concluded a peace treaty by which Bolesław ceded all claims to the land of Kladsko to Soběslav. The area thereafter remained an integral part of Bohemia, though the fief was at times held by Silesian dukes: About 1280 German kingRudolph I of Habsburg, having defeated King Ottokar II of Bohemia, gave Kladsko to his ally Duke Henry IV Probus of the Silesian Piasts, it nevertheless returned to Bohemia after Henry's death in 1290. In 1310 Count John the Blind from the House of Luxembourg by marriage inherited Bohemia and again granted Kladsko for life to the Piast dukes Henry VI the Good from 1327 to 1335 and Bolko II of Ziębice from 1336 to 1341. In 1348 the Provincia Glacensis became - still as a region within the Bohemia proper - part of the Crown of Bohemia. The town developed rapidly until the start of the Hussite Wars in the 15th century, which left Kladsko depopulated by plagues, partially burnt, and demolished by several consecutive floods. It was not until the 16th century that the local economy began to recover from the previous wars. In 1458 King George of Poděbrady with the consent of Emperor Frederick III of Habsburg elevated Kladsko to a county, held by his second son Viktorin, who thereby received the status of an Imperial count . Under his Poděbrad successors it still remained an integral part of Bohemia as an "outer region" south of the adjacent Silesian province. When in 1526 Archduke Ferdinand I of Austria from the House of Habsburg was enthroned as King of Bohemia, the County too became part of the Habsburg Monarchy; however the local counts retained their powers and the Bohemian kings ruled this land as suzerains. Since 1549 the County of Kladsko was under administration of the Wittelsbach until Albert V, Duke of Bavaria released it in 1567 for Emperor Maximilian II. In 1617 the first census was organised in the County. The city itself had approximately 1,300 houses and over 7,000 inhabitants. However, two years after the census took place the Thirty Years' War started. Kladsko had joined the Protestant Bohemian Estates and even after the defeat at the Battle of White Mountain in 1620 refused to submit to Emperor Ferdinand II of Habsburg. Between 1619 and 1649 the town was besieged by Imperial troops several times and although the fortress was never captured, over 900 out of 1,300 buildings were destroyed by fire and artillery and the population dropped by more than a half. After the war the Habsburg rulers put an end to all local self-government, and the County existed in name only.
