What is the midpoint date in a chronological list of major events in world history? At what rate does the coverage of more distant times diminish? Analysis of five lists published from 1876 to 2016 shows that the number of entries matters: Shorter lists have earlier midpoints. Normalized to 1000 entries, the midpoint of history is around 1500 CE. All lists show fewer events per century as we move to more distant past, in a coarsely exponential way. But some periods stand out. Frequency of events shows a peak from 400 to 200 BCE and a trough from 100 BCE to 1000 CE. Inclusion of less Eurocentric lists may alter this picture. But the pattern of more entries in more recent times also fits the world population explosion: More people create more memorable events. Combining this population-induced expansion of history with fading of history over time is complicated.

When some states are huge and some others tiny, an “effective number” widely used for parties in political science can be applied both to state areas and populations. These numbers decrease exponentially over 5000 years, pointing to a single world state around 3700 by area and 5000 by population. Combination with estimates from top state area and population points toward a single world state by 4600, if the 5000-year trends continue. But projections are not predictions!

A square root law of effective numbers of states applies: The population-based effective number of states and tribes tends to be the square root of the area-based number. The zone of variation around the average trends is wide. Thus, even when the average millennial trends keep holding, the immediate future is wide open. The zigzags in the past curves remind us of how fleeting human history has been. Often a mere hundred years has thoroughly altered the number and size of states. We can expect similar reversals in future.