In the late antiquity tin ore deposits were discovered in Europe and provided the impulse for the start of the Bronze Age. In Bohemia this era manifested itself in the so-called Únětice culture in the middle of the 2nd millennium BC. The raw material for bronze was the copper imported from the Alpine lands and Slovakia, while the alluvial deposits from the foothills of the Krušné hory (Ore Mountains) or Slavkovský les (Slavkov Forest) were washed for tin. The Slavkov-Krásno area represented the largest production. The first reliable evidence of it is the Arabian trader Ibrahim ibn Jakub’s report dated 965 - 966. Tin came obviously from the Teplá River placer mining and from the streams descending from stanniferous terrains in the eastern part of the Krušné hory.
In the 13th century two placer gold deposits – Krupka and Krásno – stood out. In 1241 Czech tin placers yield and quality was praised in the English chronicle Bartholomea Angelica. During colonization of the Loket region from the 2nd half of the 13th century, the processing intensity of secondary tin deposits in Slavkovský les became more important, perhaps also due to initiative of the Premonstratensian Monastery in Teplá (founded in 1193). Washing developed gradually in many places of the river-basin catchment area of the Ohře River up to Dalovice nearby Karlovy Vary.
Primary deposits began to be extracted during the 1st half of the 14th century. It is documented in the deed from 1346, listing the leasing of a property with old tin mines in the area between the Zlatý potok (Golden Brook) and Úšava u Sítin, where a monastery tin smelting works was in operation from the 1340’s. Another deposit was below the Loket Castle, written documents on which date back to 1489, but its operation is undoubtedly much older. During the colonization settlement of the Slavkovský les other alluvial deposits and placers of greisens and cassiterite lodes were uncovered. They formed an extensive zone, starting roughly at the Vysoký Kámen elevation mark, following the catchment basin area of the Slavkovský Brook all the way to Loket. Aside from these richer placers, even minor in terms of their size, stanniferous fields were processed in the area of Mariánské Lázně - Kladská - Kynžvart - Prameny along the Rota Creek, the Úšovický and Čistý Brook.
The tin mining was gradually concentrated mainly on the lower flow of the Slavkovský Brook. In the 14th century the placer mining of these deposits was so intensive that the towns of Krásno and Horní Slavkov developed from two small miners’ settlements. Written documents on the existence of the miners’ settlement Čistá date back to 1370 and of Prameny to 1380. Krásno became the administrative centre. On July 13, 1355 the owners of the Bečov domain, the nobles Bureš and Slavko of Rýzmburk, granted this town, which was then called Markt Schönfeld, the jurisdiction and administration for all placers and tin mines in the Bečov region, including the right to profit from the fees accrued from the weighing of the produced tin. The majority of sources relating to procedures of the mining and processing were destroyed within the period of 1355 - 1546 during the Schmalkaldic War of 1546 - 1547; however, there is no question that the primary deposits were first extracted by underground mining somewhere in the vicinity of Krásno.
Besides the tin mines and placers, mining on argentiferous lodes were also successful early in the 1520’s. At that time a mint for minting silver Thaler coins was built in Horní Slavkov. Due to lack of documents the duration of its operation cannot be established with certainty. It was designed to process silver from the veins coming from the Barbora, Voršila, Velký a Malý Kryštof on Borový Hill operations accessed through the Těžařská mine adit; and at the beginning of the 1540’s through the Pluhová mine adit. The reason for the mint shut down was the fact that the mines were flooded and abandoned in 1527. At the beginning of the 1530’s the works were restarted, working especially on the Pinsinger lodes. This fact is documented by issuing new mining rules for the Slavkov mining district on 1. 25. 1531, a part of which relates to silver-ore mining. However, at the end of the 16th century silver mining in this area started to decline.
Foreign producers from Nuremberg, Augsburg, and from other towns, in which the trade with Czech tin had been concentrated since the 14th century, soon began to take share in the mining business in Slavkovský les. Among the main businessmen are the names of Nützels’, Schnöds’, and Welsers’ and Fuggers’ trade houses. The foreign businessmen ensured the continuous supplies of tin from Slavkovský les to their warehouses by offering high advance-payments. Aside from them, aristocracy, especially Kašpar Pluh and Jeroným Šlik and others also participated in the mining business. However, in the early 16th century only about 6 producers were secure with the strength of their capital.
The year 1547 was a basic turning point in development of tin mining in Slavkovský les. Many foreign businessmen ceased trade relations, minor domestic producers did not manage to cover investment costs, and production started to decrease significantly. Thus one of the periods in the Slavkov and Krásno mining district history that brought this area to the leading place in European mining finished. With its high quality, the tin from the Slavkovský les deposits became standard for the European tin wholesaling and during the 1st half of the 16th century it was dominant in almost all of the main European markets.