political martyr and leader of the Genevese anti-Savoyard faction (Eidguenots) that struggled against the powerful duke of Savoy, Charles III, to maintain the independence of Geneva.

Though no more than a minor public official, Berthelier took an active part in Geneva's political controversies. In 1508 he championed the rights of military corporations against the city council, and in 1509 his protests led to the dismissal of the incumbent vidomne, the episcopal official charged with civil and criminal jurisdiction. He opposed the installation of a Savoyard puppet, John, as bishop and temporal lord of Geneva (1513) and in 1515 formed a league of patriots, the Enfants de Genève, to resist the Bishop's encroachments on citizen's rights. Further opposition to the Bishop and his Savoyard connection led to Berthelier's arraignment on a charge of lèse-majesté (March 16, 1518); and, although acquitted by the citizens' committees (syndics), he was nonetheless summarily arrested and executed. His struggles against Savoyard influence in Geneva were continued and ultimately brought to a successful conclusion under the leadership of his friend Bezanson Hugues.