Simon Marius

Simon Marius (the Latinized form of Simon Mayr; 10 January 1573 to 5 January 1625) was a German astronomer, born in Gunzenhausen near Nuremberg, who spent most of his life in Ansbach. He is best known as one of the first observers of the four largest moons of Jupiter. He published his observations in Mundus Iovialis in 1614, and his claim of independent discovery led Galileo to accuse him of plagiarism. A Dutch scientific committee in 1903 ruled in favor of Marius's independent discovery, and the mythological names by which those moons are known today, Io, Europa, Ganymede and Callisto, are the ones he gave them. He also observed the Andromeda nebula and concluded from his observations of the Galilean moons that they orbit Jupiter.