What is a Nuremberg egg

Spring-driven clock
A Nuremberg egg (German: Nürnberger Ei) is a type of small ornamental spring-driven clock made to be worn around the neck, produced in Nuremberg in the mid-to-late 16th century.

Their production was made possible by the miniaturisation of the torsion pendulum and coil spring mechanism by Nuremberg clockmaker Peter Henlein (d. 1542) at the beginning of the 16th century (c. 1505–10).

These portable watches were a novelty (although the oldest portable watch driven by wound-up clockwork rather than by weights dates to c. 1430, the so-called watch of Philip the Good), and their accuracy was very limited, so that they only had a single hand, showing hours.

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