An animation of the oldest complete geared mechanism in the world. The gears drive a calendar display on the back of a medieval astrolabe.
The instrument was made by Muhammad b. Abi Bakr in Isfahan in 1221/2 and is in the collection of the Museum of the History of Science, Oxford. For more information see the collections database at www.mhs.ox.ac.uk (MHS inv. 48213).
Find out more: https://hsm.ox.ac.uk/geared-astrolabe