Final answer:
The first rebellion against Henry IV in France was led by the Catholic League during the War of the Three Henrys. The Catholic League consisted of Catholic nobles and clergy who opposed Henry IV's rule due to his Protestant background. Henry IV eventually ascended to the throne, joined the Roman Catholic Church, and issued the Edict of Nantes granting religious toleration to French Protestants.
Step-by-step explanation:
The first rebellion against Henry IV in France was led by a group of Catholic moderates called the Catholic League.
This rebellion, known as the War of the Three Henrys, involved three factions vying for control: Henry III, Henry of Guise, and Henry of Navarre. The Catholic League was mainly composed of Catholic nobles and members of the clergy who opposed Henry IV's rule due to his Protestant background.
After the deaths of Henry III and Henry of Guise, only Henry of Navarre remained standing, and he eventually ascended to the throne as Henry IV. To bring stability to the country, Henry IV joined the Roman Catholic Church and issued the Edict of Nantes in 1598, granting French Protestants, known as Huguenots, the freedom of worship and conscience.