Eratosthenes' Measurement of Earth/Historical Note

Historical Note on Eratosthenes' Measurement of Earth
It is not certain what the length of the unit used by when he made his measurement of the circumference of the Earth.

The Olympic stade of $176.4 \, \mathrm m$ would give a circumference of $44 \, 100 \, \mathrm {km}$, an error of $10 \%$.

The Italian stade of $184.8 \, \mathrm m$ would give a circumference of $46 \, 100 \, \mathrm {km}$, an error of $15 \%$.