During the Iron Age, grain was milled by rubbing a smaller rock against a larger rock with the grain in between the discs. This was back breaking labor which is evidenced by the injuries found upon skeletal remains of ancient people. A quantum leap forward however emerged as the rotary quern, a composite tool comprised of a stone base with a wooden pole or dowel in the center, and a movable rotating top donut shaped piece which was also made of stone, but with a handle so that it could be turned. Grain was placed into the middle of the tool and because the tool was slanted upon a 45 degree angle, gravity would pull grain down. This allowed for a single person to mill much more grain than what would have traditionally been possible using antiquated Stone Age technology. This new design freed up both time spent working as well as the amount of people required to meet a specific quota (e.g. 150 – 200 grams per person per day). Because more people could be better fed, with less effort and resources, the population of those with access to the technology in Britain expanded quickly which occurred around 400 B.C.