A “nuncio” is an ambassador. Galileo identified himself as an ambassador from the stars, appointed to deliver a starry message to Cosimo II de Medici. The title page announces the four satellites of Jupiter, employing large type to name them the “Medicean stars.” Within months he was invited to Florence and established in Cosimo II de Medici’s court.
The OU copy is the only extant copy of Sidereus nuncius to contain Galileo’s handwriting. It is inscribed by Galileo as a gift to a poet in the Medici court.
Galileo presented this copy to the poet Gabriello Chiabrera (1552-1638), who was known as the “Italian Pindar.” Galileo may have hoped Chiabrera would write verses for a future Italian translation of the Sidereus, but if so, the plan fell through.