Although a baptized Catholic, Henry was raised a Protestant. Shortly after inheriting the Navarrese throne from his mother, he barely survived the St. Bartholomew's Day massacre, a series of violence against French Protestants during the French Wars of Religion.
In 1589, Henry rose to the French throne after the assassination of his brother-in-law and distant cousin, Henry III. In order to stabilize his rule, Henry converted to Catholicism in 1593, and supposedly stated that "Paris is well worth a mass". In 1600, he married Marie de' Medici. In stark contrast to Henry however, she was hated by her subjects. During his reign, he attempted in vain to set up a hospital for invalid soldiers.
In 1601, Henry announced the creation of a triangular square, later known as Place Dauphine, that was to be given to Achille de Harlay. Harlay was the first President of the Parliament of Paris, and had remained loyal to Henry during the Wars of Religion. Near the square, a bronze equestrian statue dedicated to Henry was installed in 1614.
From 1605, Henry oversaw the design of the 36 pavilions of the Place Royale, later known as the Place des Vosges. He requested perfect symmetry, with four arcades and two rows of high windows for each pavilion. Around this time, he accepted Christophe Marie's proposal to build a double wooden bridge across Île Saint-Louis, which would be finished after the King's death. He also enlarged the Tuileries Palace, connecting it to the Louvre.
In 1610, Henry was assassinated by the Catholic fanatic François Ravaillac while riding his carriage. Following his death, he was succeeded by his son, Louis XIII. Henry's grandson, Charles, would become King of England.