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The Encyclopedia of Horology

Paris, France · c. 1365–1436

Jean Fusoris

Partially verified

Maker of astrolabes, astronomical clocks, and scientific instruments

Life & work

Born in Giraumont, Jean Fusoris initially learned metalworking from his father before pursuing studies in arts, medicine, and theology at the University of Paris.

Fusoris held several ecclesiastical positions throughout his career, including roles as a canon at Rheims and Notre-Dame, while maintaining his scientific activities. His reputation led to commissions from high-ranking individuals, including King Henry V of England and the Bishop of Norwich, Richard Courtenay. During his later years, he was commissioned to construct the monumental astronomical clock for the Bourges Cathedral in 1424.

Fusoris remains recognized for introducing significant technical improvements to the astrolabe, including the use of an ostensor and a specific tympan for geographic problem-solving.

The fuller biography summarises the open references listed under Sources; each statement was checked against the cited passage. Confirm key dates in period documents before relying on them.

Training, contributions & innovations

  • He improved the sighting system on the astrolabe alidade by adding a small pin in the line of sight for enhanced precision.

Documented works

  • The astronomical clock of the Bourges Cathedral, designed in 1424, is one of the oldest surviving examples in France.

Collecting significance

The catalogued pieces listed on this page show the kinds of objects auction houses, dealers and museums attribute to this maker; each attribution is the source's own.

Firms, key models & movements

No firm, model or movement in this encyclopedia is yet recorded under this maker's name.

In the object catalogue

3 catalogued objects are recorded under Jean Fusoris. Attributions are as given by each source and are not independent authentication.

Diagram

12345let downstripcleanoilregulateorder of work; never skip letting down the mainspring
Schematic: order of work at the bench. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

  1. Jean Fusoris, Wikipedia (English), retrieved 2026-11-03 (text CC BY-SA 4.0)
  2. Jean Fusoris, Wikipedia (French), retrieved 2026-11-03 (text CC BY-SA 4.0)
  3. Horloge astronomique de Bourges, Wikipedia (French), retrieved 2026-11-03 (text CC BY-SA 4.0)
  4. Fusoris Jean, Watch-Wiki, retrieved 2026-11-03

Where sources disagree, the disagreement is stated rather than resolved silently.