By about 2800 BCE, Babylonians were making a soap-like substance by boiling fats with ashes, and clay tablets record the recipe. But it was mainly used to wash wool and textiles or as medicine, rather than for daily washing. Lathering up your hands is a much more recent habit.
Around 2300 BCE, Enheduanna, daughter of King Sargon of Akkad, became high priestess of the Moon god at Ur. She composed hymns to the goddess Inanna and put her name to them. She is the oldest person identified as the author of a literary work, about 1,500 years before Homer.
Squeeze Earth's 4.5 billion years into a single 24-hour day. Homo sapiens shows up around 11:59:54 p.m., roughly six seconds before midnight. All of written history, from Sumerian tablets to today, fits into the final tenth of a second. A cosmic blink.