At the grand-duke 's suggestion , Galileo changed the name to Medicea Sidera ( ` the Medici stars ' ) , honoring all four Medici brothers ( Cosimo , Francesco , Carlo , and Lorenzo ) . At Cosimo 's suggestion , Galileo changed the name to Medicea Sidera ( `` the Medician stars '' ) , honoring all four Medici brothers ( Cosimo , Francesco , Carlo , and Lorenzo ) .