The Treaty of Tours (30 April 1589) saw a dramatic reversal of the alliances during the Eighth War of Religion, after Henry III of France was forced into an alliance with his former foe, the Huguenot leader Henry of Navarre.
At the end of 1588 Henry III had assassinated Henry, duke of Guise and his brother Louis, Cardinal of Guise, in a desperate attempt to gain control of the Catholic League. This almost immediately backfired on him. Henry failed to act decisively after the death of the two Guises, and events soon slipped out of his control. Command of the League passed to Guise’s brother Charles, duke of Mayenne. Paris had already repudiated Royal authority, but the city now turned on Henry III himself, with the Sorbonne and the Parlement both declaring him deposed as king. The murder of the Cardinal also meant that the church turned on him. All across France major towns were taken over by League supporters.
Henry III’s only option was to turn to the Huguenot leader Henry of Navarre for aid. Negotiations began at Tours in March, and the treaty was agreed at the start of April. The two men met in the park of Plessis-les-Tours on 30 April and signed the treaty of Tours.
A truce was agreed between the Royal and Huguenot forces, to last for one year from 3 April. The Huguenots were to be allowed to keep any towns that were currently in their hands. Navarre was given the fortified town of Saumur (to give him a bridge over the Loire) and one additional town in each bailiwick of France. The Huguenots were not to be persecuted during the truce. In return the Huguenots agreed to help Henry III defeat the League.
In an attempt to preserve his Catholic credentials, Henry III announced that he hoped that Henry of Navarre was about to convert to Catholicism.
After the signing of the treaty, Henry III and Henry of Navarre combined their armies and besieged Paris. However on 1 August 1589 Henry III was assassinated by a Jacobin monk, Jacques Clément. Henry of Navarre now became King, changing the nature of the war. At this point, with two of the three Henrys dead, the Eighth War of Religion, becomes the Ninth War of Religion, effectively a succession war to see if the new Henry IV could hold onto his throne.