The gold ultimately came from the upper reaches of the Niger River and Volta River and the Portuguese crown aimed to divert the gold trade towards the coast. To control this trade, the king ordered the building of a castle, called São Jorge da Mina (now Elmina Castle), on the Portuguese Gold Coast in 1482 and other trading posts. The Portuguese government instituted the Company of Guinea to deal with the trading and to fix the prices of the goods. Besides gold, ivory, Melegueta pepper and slaves were traded. It is estimated that the Atlantic slave trade transported around 11 million people from Africa between 1440 and 1870, including 2 million from Senegambia or Upper Guinea.