Henry of Navarre, also known as King Henry IV of France, ended the long, bloody War of the Three Henrys between Catholics and Protestants in 1594 after converting to Catholicism. Four years later, he helped to negotiate the Peace of Vervins between Spain and France.
After the death of King Henry II and his heir Francois, Henry of Navarre became the heir to the French throne. However, this was strongly opposed by Catholics, leading to Pope Clement VIII excommunicating Henry from the church. At this time, Henry III became King of France, despite Henry of Navarre being the heir, which led to the War of the Three Henrys. Henry of Navarre was also opposed by Henry the Duke of Guise.
During this conflict, King Henry III eventually sided with Henry of Navarre due to the Duke of Guise enlisting the help of Spain in the conflict. Eventually, Henry III named Henry of Navarre as his heir soon before he died. However, it took another nine years before he could finally claim his throne, after finally taking control of Paris in 1594.
Soon after, Henry IV negotiated the peace treaty with Spain, he then issued the Edict of Nantes, which called for an end to hostilities between Catholics and Protestants, eventually restoring peace to France.