Sumer
Sumer () is the earliest known civilization in the historical region of southern Mesopotamia, modern-day southern Iraq, during the Chalcolithic and Early Bronze ages, and one of the first civilizations in the world along with Ancient Egypt and the Indus Valley. Living along the valleys of the Tigris and Euphrates, Sumerian farmers were able to grow an abundance of grain and other crops, the surplus of which enabled them to settle in one place. Prehistoric proto-writing dates back before 3000 BC. The earliest texts, from c. 3300 BC, come from the cities of Uruk and Jemdet Nasr; early cuneiform script emerged around 3000 BC.
Threshing board
The threshing boards must have been important in the protohistory of Mesopotamia, since they already appear in some of the oldest written documents discovered: specifically, several sandstone tablets from the early town of Kish (Iraq), engraved with cuneiform pictograms, which could be the world's oldest surviving written record, dating to the middle of the 4th millennium BC (Early Uruk period). One of these tablets, preserved in the Ashmolean Museum of Oxford University, appears to have pictures of threshing boards on both faces, next to some numeric symbols and other pictograms. These presumed threshing boards (which might instead be sledges) have a shape similar to threshing carts that were used until recently in parts of the Middle East where non-industrial agriculture survived. Descriptions also appear in numerous cuneiform clay tablets as early as the third millennium BC.