Galileo Galilei's Sidereus Nuncius or The Starry Messenger was published in 1610. The main benefactor of the findings published in this book was Cosimo II de'Medici, a former pupil of Galileo (who taught him mathematics four years prior to this work) who became the Grand Duke of Tuscany. In order to gain the patronage of the Grand Duke, Galileo named the four moons of Jupiter as the Medicean Stars, in honor of the Cosimo and his three royal brothers. Galileo dedicated this work to Cosimo and sent him an advance unbound copy of his book (along with a bound copy) along with the telescope he used to make these discoveries. The words "Medicean Stars" were actually written on the title page of the book to attract Duke's attention and formalize the "gift".
Interestingly, astronomers renamed the four moons of Jupiter after the discoverer and these are now collectively called Galilean Satellites (individually named as Io, Europa, Ganymede and Callisto).