Sidereus Nuncius is a short astronomical treatise published in Neo-Latin by Galileo Galilei on March 13, 1610. It was the first published scientific work based on observations made through a telescope, and it contains the results of Galileo's early observations of the imperfect and mountainous Moon, of hundreds of stars not visible to the naked eye in the Milky Way and in certain constellations, and of the Medicean Stars that appeared to be circling Jupiter.

Neo-Latin is the style of written Latin used in original literary, scholarly, and scientific works, first in Italy during the Italian Renaissance of the fourteenth and fifteenth centuries, and then across northern Europe after about 1500, as a key feature of the humanist movement. Through comparison with Latin of the Classical period, scholars from Petrarch onwards promoted a standard of Latin closer to that of the ancient Romans, especially in grammar, style, and spelling. The term Neo-Latin was however coined much later, probably in Germany in the late 1700s, as Neulatein, spreading to French and other languages in the nineteenth century. Medieval Latin had diverged quite substantially from the classical standard and saw notable regional variation and influence from vernacular languages. Neo-Latin attempts to return to the ideal of Golden Latinity in line with the Humanist slogan ad fontes.