Communication · c. 3,500 BCE

Cylinder seal

A carved stone cylinder rolled over wet clay prints a unique signature, again and again.

Mesopotamian officials rolled engraved cylinders across clay to mark ownership and authorise transactions, from about 3500 BCE. Seals were the first repeatable printing of an image and a working identity system for early bureaucracies.

See it in the living tree Wikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

Clay accounting tokens 8000 BCE

What it led to 3

Proto-cuneiform 3350 BCE
Egyptian hieroglyphs 3250 BCE
Woodblock printing 700

Related measurements

The dashed line marks when it first worked.

Share of people living in cities Latest: 57.5 % (2025) Source: Our World in Data

World GDP over a million years Latest: 41k billion 1990 international $ (2000) Source: DeLong 1998, Estimating World GDP, One Million B.C. - Present; Wikipedia: Gross world product (DeLong table, cross-check)