Some 4,000 to 5,000 years ago, farmers from the area of today's Nigeria–Cameroon border began spreading south and east. Over millennia, this 'Bantu expansion' carried farming and ironworking across much of the continent. The result: around 500 related languages, now spoken by hundreds of millions of people.
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.