Casyopée was born from research and development projects for 15 years within the IREM (Institut de Recherche sur l'enseignement des Mathématiques) of Rennes in Brittany.

Among the main contributors along the years:

• Roselyne Halbert teaches at the lycée Zola of Rennes.
• Jean-baptiste Lagrange was professor at the University of Reims, and is now a volunteer at the Laboratoire de Didactique André Revuz, University Paris Diderot.
• Christine Le Bihan teaches at the lycée Joliot-Curie of Rennes.
• Bernard Le Feuvre was a teacher at the lycée Cassin of Montfort (Ille et Vilaine). Deceased in July 2019, Bernard was to the end, and in spite of his illness, one of the main facilitators and contributors of the project. 
• Xavier Meyrier was a teacher at the lycée Maupertuis of Saint Malo (Ille et Vilaine) et is now Inspecteur Pédagogique in Mathématiques.
• Marie-Catherine Manens was a teacher at the lycée Zola of Rennes and contribues now as a volunteer.

Many teachers, researchers and developers took and take part in the software design, in developing uses and resources. It is a lively community, open to everybody interested. Every contribution is welcome from simple remark on ergonomics or software functioning , to proposition of new facilities, through report and reflection about  uses.