As explained in the entry on flour, this domestic device led to others, the harnessing of water power in classical Rome, and the adoption of wind power from about AD 1000. However, the principle remained the same and the grinding had to be followed by sieving or bolting, until the 19th century when something quite new emerged: the efficient, fast roller mill, first tried in Hungary in the 1820s, perfected in Switzerland in 1834, and then quickly adopted all over Europe and America. Its multiple steel rollers not only ground the grain, but also separated the various fractions (bran, germ, endosperm). For the first time, truly white flour was available at a low price.