Number Pi from the Decorations of Ancient Artifacts

The decorations of ancient objects can provide some information on the value of constant π as a rational number, known and used by the artists who made them. Number π is the dimensionless ratio of circumference to diameter, and then, by measuring the ancient decorations we can obtain its value and gain some hints on the human knowledge of mathematics and geometry in prehistoric times. Here we discuss two examples of this approach. The first is concerning some disks found in the tomb of Hemaka, the chancellor of a king of the First Dynasty of Egypt, about 3000 BC. The second is the decoration composed by several circles and spirals of the Langstrup belt disk, an artifact of the Bronze Age found in Denmark.