Kongsberg Silver works () was a mining operation at Kongsberg in Viken county in Norway. The town of Kongsberg is the site of the Norwegian Mining Museum (). History Operating from over 80 different sites, Kongsberg silver mines constituted the largest mining field in Norway. It was the largest pre-industrial working place in Norway, with over 4,000 workers at its peak in the 1770s and supplied over 10% of the gross national product of the Danish–Norwegian union during its 335-year-long history: over 450,000 man-years were expended in the production. The silver mines in Kongsberg were in operation from 1623 until 1958. Total production exceeded 1,3 million kg silver. Silver was first discovered between the 1 July and 5 July 1623, according to the somewhat romanticized story, which tells of two small children - Helga and Jacob - who were out shepherding their cattle at the top of Gruveåsen hill. They had an ox with them which scraped on the side of the mountain. They could see something shining and glimmering, and they picked it up and took it home to their father. Recognizing it as silver and quite valuable, he melted it and brought it to the town of Skien in Telemark county to sell it. In Skien he was arrested, the police finding it suspicious that someone would attempt to sell silver at such a low price. Being convinced that he was a thief, he was given the choice between telling where he had found the silver, or being sentenced to hard labour. He chose to tell the authorities he had found the silver in Southern Sandsvær, which was the old name for Kongsberg. But silver mining in Gruveåsen had been established well before then, and was referred to as the Argenti Fodinæ (Latin for "The Silver Mines") in a source from 1532, Jacob Ziegler's book about Scandinavia. In 1539, a silver mining venture proper had been started by Christian III's with imported expert German miners. At the time, the newly discovered sea route to India and the Far East had prompted a scramble to search for silver to finance trade, but the Gruveåsen mines were then shut in the first half of the 1540s when the price of silver fell sharply due to large amounts of silver flowing from Spanish Latin America. The price of silver eventually recovered in the latter half of the 16th century on increased