Why were Huguenots allowed to keep fortified towns under the Edict of Nantes?

Under the Edict of Nantes, Henry IV granted the Huguenots the right to maintain fortified towns, known as places de sûreté, specifically as a surety against attack.12

These strongholds were intended to provide the Protestant minority with military security and protection following decades of violent conflict during the Wars of Religion. By allowing the Huguenots to garrison these locations—such as La Rochelle and Montpellier—the king sought to ensure their safety and maintain a fragile peace while he worked to restore royal authority and unify the state. The crown initially agreed to cover the expenses of garrisoning these sites for a period of eight years.12

However, these military concessions were highly controversial and were later viewed by figures such as the Cardinal de Richelieu as a threat to the state's integrity, eventually leading to their removal by the Peace of Alès in 1629.13