“Arago the Great” was the oldest of the six Arago brothers, who also included the writer-explorer Jacques and the writer-politician Etienne. A well-known physicist, he dedicated himself to optics and astronomy, focusing particularly on how light is transmitted. He was one of those who spoke out strongly in favor of the Daguerreotype on January 7, 1839 at a conference at the Academy of Science, whose perpetual secretary he was. A Republican parliamentarian, he became Minister of War in 1848. Later, he refused to bow down to either Louis-Napoléon Bonaparte or the Empire, but, in poor health, he died on October 2, 1853, while the Pantheon was being prepared. His political convictions and strong ethics naturally brought him and Nadar close.