Henry IV's alliance with his royalist towns harkened back to the moment on 1 August 1589 when Jacques Clement drove his dagger into Henry III and brought the Valois succession issue to a head. Childless and dying, Henry III was forced to name a successor to the throne, and in his final moments he recognized his brother-in-law, Henry of Navarre, as the legitimate new king of France by hereditary right. This acknowledgement should have ensured Henry the throne. But the Catholic League was well-entrenched in the majority of French cities and towns, and zealous Catholics refused to accept a Protestant king. As the news of Henry III's assassination spread, few towns came forward to recognize the king. In 1589 Henry's power base thus consisted of about one-sixth of the country, and most of this support was from Huguenot towns and nobles in the southwest. Only a handful of non-Protestant royalist towns accepted Henry as king.

Henry IV's relationship with Huguenot towns was far more complex than his affiliation with either League or royalist municipalities. League towns in 1589 perceived Henry as a heretic and a usurper; royalist towns viewed him as their king and ally. For the Protestant towns, Henry was the protector of the Huguenot movement. His relationship with the Protestant nobility and the towns stretched back to his boyhood. He became titular head of the Huguenot movement when he was only fourteen years old, and he spent most of his young manhood campaigning with the Huguenot armies. During the 1580s he consolidated his control over most of southwestern France.