Early history until the Thirty Years' War
There are legends accrediting the beginnings of the town to Celtic tribes. In the 1st century A.D. Germanic tribes came, but moved on in the great Germanic migration to the west. In the 6 th century the country was settled by Slaves. Some talk about a castle on Úhošť hill that might have been called Wogastisburg where a battle between Franks and Slavs occurred in 631. The battle of Canburg in 805 is also often mentioned in connection with the town, but is a mistake because locality of this name (Canburg - Kanina) is in Middle Bohemia.
The first written record is, though, of the end of the 12th century - the Czech prince granted the "market town" of Kadaň to the Knights of St. John. Slavic rulers called German settlers into the country, offering them freedom but gaining taxes at the same time. The Knights Hospitaller built the first church in Kadaň - St. John the Baptist - which still stands in the part of town called Hospitaller Suburb, but is now in the Baroque style. In the 13th century, the town was promoted to a "Royal City". It began to thrive and a new town was built on the heights above the river, with a castle and Franciscan monastery. There was a big fire in 1362. However, Emperor Charles IV who twice visited the city (1367 and 1374) granted it several municipal rights (home rule, a vineyard, and an annual market) that made it flourish again. The reign of Wenceslaus IV (Václav IV) produced the skilled clockmaker Mikuláš of Kadaň (Mikuláš z Kadaně), who, together with mathematician and astronomer Jan Šindel, designed the Prague Orloj.
The 15th century brought a new dimension to the history of Kadaň: the town and castle often used to be pledged to royal creditors. At the end of the rule of George of Poděbrady first the town and later the castle was captured by Jan Hasištejnský z Lobkovic (John of Lobkowicz and Hassenstein), who seemed to see Kadaň as a
