Jourdan law

The Jourdan Law of 1798 (loi Jourdan) effectively institutionalised conscription in Revolutionary France, which began with the levee en masse.It stipulated that all single and childless men between the ages of 20 and 25 were liable for military service.Exemptions existed however for the clergy, industrial workers essential for the war-effort, students from selected Grandes écoles, and public office holders.
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