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Deep Time on a History Timeline: Seven Million Years Before the First City

Written history runs about five thousand years. The human family tree runs about seven million. Here is what fills the gap and how the dates are fixed.

By Published 5 min read

Reign Creative LLC makes World History Timeline Sim, which this article links to, so we have a commercial interest in it. How we write and check articles.

Key takeaways

  • The answer depends on the word: written history runs roughly five thousand years, while the human family tree runs six to seven million, so the two questions need separating before either can be answered.
  • The Smithsonian places Sahelanthropus tchadensis, from Chad, at between seven and six million years ago, near the point at which the hominin line diverged from other apes.
  • Stone toolmaking was long dated to at least 2.6 million years ago, then pushed back by the 3.3-million-year-old assemblage published from Lomekwi 3 in West Turkana, Kenya.
  • Fossils from Jebel Irhoud in Morocco, dated by thermoluminescence to 315 thousand years with a stated uncertainty of 34 thousand, are the oldest well-dated evidence for early stages of our own species.
  • A timeline that spans both deep time and recorded history is unreadable at one scale, which is why the useful move is to browse each band separately rather than zoom between them.

Human history goes back about five thousand years or about seven million, depending on which word you stress. Written records begin a few thousand years ago and are what most history timelines actually contain. The human family tree is roughly a thousand times older than that, and almost all of it is studied through fossils, stone and sediment rather than documents. Both answers are correct; conflating them is what makes the question feel unanswerable.

The deepest end: six to seven million years

The Smithsonian's Human Origins Program describes Sahelanthropus tchadensis, known from West-Central Africa in present-day Chad, as living sometime between seven and six million years ago, and as one of the oldest known species in the human family tree. The same source places the divergence of the first hominins from other apes somewhere between six and seven million years ago in Africa.

What makes a fossil that old readable as a relative of ours is anatomy rather than resemblance: small canine teeth, and evidence for walking upright on two legs. In this case the argument for bipedalism rests on the position of the foramen magnum — the opening where the spinal cord enters the skull — which indicates the head was held on an upright body.

That is a good illustration of how the deep end of the record works. The claim is an inference from a measurable feature, stated with its basis attached, and it is open to revision if better material appears. The Natural History Museum notes that more than twenty hominin species are now recognised, with at least half resting on fossils unearthed in the last thirty years.

The tool record, and a date that moved

Stone tools are the first evidence of behaviour rather than anatomy, and their dating has shifted within living memory.

The Smithsonian's summary is that stone toolmaking developed by at least 2.6 million years ago, with Oldowan toolkits consisting of hammerstones, stone cores and sharp stone flakes, known from sites including Lokalalei in Kenya, Olduvai Gorge in Tanzania and Majuangou in China.

Then, in 2015, a team publishing in Nature reported Lomekwi 3, a site in West Turkana, Kenya, where stone artefacts were found in place alongside Pliocene hominin fossils in a wooded environment, dated to 3.3 million years ago. The authors argued the knappers combined core reduction with battering, proposed the name "Lomekwian" for the assemblage, and noted that it predates the Oldowan by about 700,000 years — which also undercut the older assumption that toolmaking began with the genus Homo and was driven by the spread of grasslands.

Both figures remain in circulation, because they describe different things: one is the date of a well-established and widespread industry, the other the date of a single earlier site. That distinction is worth carrying into any deep-time date you read.

When our own species appears

Fossils from Jebel Irhoud in Morocco, published in Nature in 2017, were dated by thermoluminescence to 315 thousand years with a stated uncertainty of 34 thousand. The authors described a mosaic of features — facial, jaw and dental anatomy close to modern humans, combined with a more primitive braincase — and argued the site documents early stages of the Homo sapiens lineage, with the further implication that the process involved the whole African continent rather than one region.

Notice the form of that claim. It is a dated measurement with an error range, an anatomical description, and an interpretation, kept separate from each other. Popular retellings usually flatten all three into a single round number. How historians date events covers why that flattening matters and how the underlying methods behave.

Where prehistory stops

The boundary between prehistory and history is about evidence, not about the people. It falls wherever written records begin, which is a different date in every region and is not a date at all in places where early writing was never used or has not survived.

That has two consequences worth stating plainly. Regions without early writing are not "outside history"; they are studied with a different toolkit. And the line is a property of the surviving record, so it moves when new material is found or deciphered. The major eras of world history covers how this boundary sits inside the wider period scheme and why the labels around it are arguments rather than facts.

Why deep time breaks a timeline

Here is the practical problem. If a timeline runs from seven million years ago to the present at one scale, then all of recorded history occupies roughly the last 0.07 per cent of it. Every written event — every empire, war, book and invention — falls inside a sliver too thin to render. Zoom in far enough to read that sliver and the fossil record vanishes off the far end.

There is no display that solves this. What works instead is treating deep time and recorded history as separate bands with separate reading strategies:

  • In deep time, read intervals. The useful statements are "about a million years apart" and "roughly contemporary", because the error bars are often larger than all of recorded history.
  • In recorded history, read sequence. Here the interesting question is usually what came before what, and by how much, with dates often good to the year.
  • Never compare precision across the boundary. A date given as 2.6 million years and one given as 44 BCE are both dates, and they are not the same kind of object.

World History Timeline Sim is our own app, built by Reign Creative, and it handles this the ordinary way: a prehistory band sits at the far end of the range, with the great majority of its entries concentrated in the recorded period. Browsing the prehistory band on its own, rather than scrolling into it from the classical era, is the reading that actually works. It is an exploration tool for getting your bearings, and not a substitute for the museum collections, excavation reports and peer-reviewed papers where these dates are established — the Smithsonian and Natural History Museum pages cited here are free and are the better place to check a specific claim.

For orientation on using a chronology well, see how to actually learn something from a timeline app. More chronology material sits in the world history timelines hub, and our other learning apps are listed under education and brain games.

Good to know

Frequently asked questions

Where does prehistory end and history begin?
At the arrival of written records, which happens at different times in different places — so the line moves around the map rather than sitting at one global date. It is a statement about the kind of evidence available, not about a change in the people being studied. Regions with no early writing are studied through archaeology, oral tradition and linguistics instead.
How old are the oldest stone tools?
The Smithsonian's Human Origins Program states that stone toolmaking developed by at least 2.6 million years ago, the date associated with Oldowan assemblages. A 2015 paper in Nature reported an older assemblage from Lomekwi 3 in West Turkana, Kenya, dated to 3.3 million years and proposed as a distinct industry predating the Oldowan by about 700,000 years.
How many human species have there been?
The Natural History Museum in London notes that more than twenty hominin species are now recognised as part of our family tree, and that at least half of them rest on fossils found in the last thirty years. That rate of discovery is why any count should be read as current rather than final, and why species boundaries in this field are frequently revised.
Why do deep-time dates come with plus-or-minus figures?
Because they are measurements, not records. Techniques such as thermoluminescence and radiometric dating estimate elapsed time from a physical property and carry a calculable uncertainty, which is reported alongside the result. The Jebel Irhoud fossils, for example, are published at 315 thousand years plus or minus 34 thousand — a range, not a point.

Sources

  1. Sahelanthropus tchadensis (opens in a new tab)Smithsonian National Museum of Natural History, Human Origins Program — accessed
  2. Stone Tools (opens in a new tab)Smithsonian National Museum of Natural History, Human Origins Program — accessed
  3. 3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya (opens in a new tab)Nature — accessed
  4. New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens (opens in a new tab)Nature — accessed
  5. Human evolution (opens in a new tab)Natural History Museum, London — accessed

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