European traders would barter commodities and goods with local people. There are many opportunities for entrepreneurs to start a barter exchange. Moreover, each has created its own currency through which its member barter companies can trade. Sheep themselves may be a medium of trade in barter economies. However trade by barter did also take place between them. During the ritual, they barter their souls with Satan in exchange for wealth and power. They are also the basis for more recent barter exchange systems. Adam Smith anchored his economics in the supposed human "propensity to truck, barter and exchange". Trade was also conducted through a mechanism of barter and credit. These goods were first exchanged by barter. Kisumu literally means a place of barter trade "sumo". The largest b2b barter exchange is Tradebank, founded in 1987. Historically, prices were established through a system of barter or negotiation. Money gradually came to be replaced by barter and a system of coupons. Direct buying from farmers in the countryside and barter against cigarettes became common.