As the first city-states started to form in ancient Mesopotamia, fed by a patchwork of farms across the fertile land between the Tigris and Euphrates rivers, grain was stored in large siloes (in case of future shortages), and a surplus was generated for the first time, that was accumulated and controlled by a warrior class drawn from Mafia-like, oligarchic families, assisted by a priesthood that kept records and legitimized their rule via a mandate from the heavens.