The stronger the tribe, the more they engage in trade. Bartering begins, exchanging goods for goods or services.
Lands hold in fee.
Learned they could enslave people. Political groups evolve. Rent and trade begins. The Church prescribes rules for economic conduct that were compatible with its religious doctrines. Farmers were frequently deprived of their harvest as a result of incursions by foreign tribes, they decided to band together and provide their own protection.