Writing
The invention of the first writing systems is roughly contemporary with the beginning of the Bronze Age of the late 4th millennium BC. The Sumerian archaic cuneiform script and the Egyptian hieroglyphs are generally considered the earliest writing systems, both emerging out of their ancestral proto-literate symbol systems from 3400 to 3200 BC with earliest coherent texts from about 2600 BC. It is generally agreed that Sumerian writing was an independent invention; however, it is debated whether Egyptian writing was developed completely independently of Sumerian, or was a case of cultural diffusion.
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.