For over 2000 years, millstones were the best way to grind grain in humanity's struggle against hunger, and no alternative method became widely popular until around 1870, when roller mills cut grain between corrugated steel rollers. The method of grinding grain between a rotating upper stone and a stationary lower stone was developed over 2000 years ago, and the first mill of this type, turned by hand, was known as a quern, the direct ancestor of the larger millstones used in water-powered mills. Other grain-processing methods included pounding grain with a rock, using a mortar and pestle to pound corn into cornmeal, and rubbing grain with a small stone back and forth to form a saddle-shaped concavity known as a saddlestone. Among traditional millstones, some uncommon cone-shaped underrunner stones turned the bottom stone, while in pairs often called buhrs only the upper runner stone revolved above a stationary lower bedstone.