(1519-1589) Queen of Henry II of France. Her political career began with the accession of her son Francis II (1559), and continued during the reigns of her sons Charles IX and Henry III. The period was one of conflict between the Huguenots under the Prince de Conde and the Admiral de Coliguy, and the Catholics led by the House of Guise. The culmination of the struggle was the Massacre of Saint Bartholomew's Day. Catherine lacked religion; she fluctuated between Catholics and Protestants; and her actuating principle was the furtherance of her own political power.