About 3500 years ago scribes were marking symbols on clay tablets. It is described as cuneiform writing, cuneiform means wedge-shaped, because of the marks they made into the wet clay using the stem of Papyrus reeds (Cyperus papyrus) which are wedge shaped. Then the tablets were fired. This has meant that many have been preserved.
At first the tablets were used to record commercial transactions. The one shown is a bill of sale for a field and house. But later the symbols developed, enabling the recording of poetry and epic tales.