The indigenous Guaraní and some Tupí communities (whose territory covered present-day Paraguay) first cultivated and used yerba mate prior to European colonization of the Americas. Its consumption was exclusive to the natives of only two regions of the territory that today is Paraguay, more specifically the departments of Amambay and Alto Paraná. Only after the Jesuits discovered its commercialization potential, that it became widespread throughout the province and even to others in the Spanish Crown. The leaves of the plant are steeped in hot water to make a beverage known as "mate". When served cold, it is called "tereré" in the Guarani language. Both the plant and the beverage contain caffeine.