In 1829, Niépce entered into a partnership with Louis Daguerre, who was also seeking a means of creating permanent photographic images with a camera. Together, they developed the physautotype, an improved process that used lavender oil distillate as the photosensitive substance. The partnership lasted until Niépce's death in 1833, after which Daguerre continued to experiment, eventually working out a process that only superficially resembled Niépce's. He named it the "daguerréotype", after himself. In 1839 he managed to get the government of France to purchase his invention on behalf of the people of France. The French government agreed to award Daguerre a yearly stipend of 6,000 francs for the rest of his life, and to give the estate of Niépce 4,000 francs yearly. This arrangement rankled Niépce's son, who claimed Daguerre was reaping all the benefits of his father's work. In some ways, he was right—for many years, Niépce received little credit for his contribution. Later historians have reclaimed Niépce from relative obscurity, and it is now generally recognized that his "heliography" was the first successful example of what we now call "photography": the creation of a reasonably light-fast and permanent image by the action of light on a light-sensitive surface and subsequent processing.