Rhine03 Rheinfels Castle, overlooking the town of St Goar, was built in 1245. In 1255/56 the Rhemish League besieged the castle unsuccessfully for one year and fourteen weeks in response to an increase in the Rhine tolls. Such a drastic response to toll increases may be better understood when you consider that a merchant typically used up to 90% of the goods he started with to pay the people and animals pulling his barge and to these "robber barons" in castles along the way. If the tolls were increased, the merchant may well arrive in Rotterdam with literally nothing to sell. The Rheinfels was the most powerful castle and fortress on the Rhine for half a millennium. 200 years after its destruction, its imposing ruins still present an impression of its earlier power and formidable size.