A chapel at villam Ratehtim was first mentioned in an 1177 deed, then part of the Millstatt Abbey estates within the Duchy of Carinthia; it was raised to a parish in 1262. Since the Middle Ages Radenthein had been an iron ore and garnet mining area and the site of a finery forge, even the use of reverberatory furnaces is documented since the late 18th century.
A chapel at villam Ratehtim was first recorded in a document from 1177, then became part of the Millstatt Abbey estates within the Duchy of Carinthia and was upgraded to a parish in 1262. Historically, Radenthein has been known for its iron ore and garnet mining activities, as well as its use of advanced furnaces since the late 18th century.