Forced to reduce their activities in the Black Sea, and at war with Venice, the Genoese had turned to North African trade of wheat, olive oil (valued also as an energy source) and a search for silver and gold. Europeans had a constant deficit in silver and gold, as coin only went one way: out, spent on eastern trade that was now cut off. Several European mines were exhausted, the lack of bullion leading to the development of a complex banking system to manage the risks in trade (the very first state bank, "Banco di San Giorgio", was founded in 1407 at Genoa). Sailing also into the ports of Bruges (Flanders) and England, Genoese communities were then established in Portugal, who profited from their enterprise and financial expertise.