Henry of Navarre became the nominal ruler of France after the assassination of Henry III of France (r. 1574-1589), whose marriage to Louise de Lorraine produced no heir. After years of attempts to deny the throne to Navarre, his enemies realized they could not defeat him militarily. The French Wars of Religion had exhausted the country, and it became clear that Henry would need to adopt the religion of the majority of his subjects to assure the freedom of conscience for Protestants with whom he had a religious affinity and who had fought by his side.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/2031/henry-iv-of-france--the-edict-of-nantes/.