By using an integrated dynamic model we are able to reconstruct the supply and gold price of the past (1920-2010) and this is used to predict the future supply of gold to the market and to make a forecast of the goldprice 2010-2100. The model was validated against field data for the period 1920-2010 and it performs well. The model GOLD is implemented in the STELLA® software and the model described in the article. The simulation results show that the market is fundamentally driven by supply and demand, but that derivates trade and speculations have affected the market significantly to create large short term variations in price. The investigations show that during 1930 to 1971, the price was set by the governments of the US and UK, that afte...