Personalities connected with the Dialogue

Federico Cesi (1585–1630)

Federico Cesi was a prince from a distinguished Roman family. In 1603 he founded – together with Francesco Stelluti, Anastasio de Filiis and Johannes Eck – the Accademia dei Lincei, which from 1610 supported academic courses and paid for the resulting works to be published. From 1611 Galileo was a member of the academy, where he published both his Lettere solari (1613) and the Saggiatore (1623). The costs of publishing the Dialogue are also said to have been assumed by Prince Cesi but he died unexpectedly on 1 August 1630.

Giovanni Ciampoli (1589–1643)

Born in Florence, Giovanni Ciampoli had known Galileo since early childhood and remained a close and loyal friend. After Ciampoli had entered the service of the church, Pope Gregory XV appointed him secretary, responsible for issuing pontifical Briefs in Latin ("segretario dei brevi"). He was received by Prince Cesi into the Accademia dei Lincei, and he also enjoyed the trust of Pope Urban VIII and undoubtedly had influence on the granting of the imprimatur for the Dialogue.

He was disgraced in 1632 because he was suspected of having supported the Spanish faction led by Cardinal Borgia. His goodwill towards the Dialogue may also have harmed him. On 24 November of the same year Giovanni Ciampoli was banished from Rome. For Galileo, this meant the loss of his most important advocate in the Papal Court.

Virginia Galilei, Sister Maria Celeste (1600–1634)

Virginia was the eldest of the three children of Galileo and Marina Gamba of Padua, with whom Galileo lived unmarried for many years. Galileo placed Virginia, then aged 13, together with her sister, a year younger, in the Poor Clares convent in Arcetri near Florence while he later legitimated and financially supported his son. At the age of 16, Virginia became a nun under the name of Sister Maria Celeste.

Letters from Virginia to her father, of which 124 survive from the period 1623–1633, attest to a close relationship between them. These letters show that Galileo occasionally helped the poor convent with material and financial assistance and that Virginia supplied him with medicines from the convent’s pharmacy and took care of domestic, family and financial matters during the trial against the Dialogue.

Ferdinando II de' Medici (1610–1670)

Grand Duke of Tuscany. It was to him, then only just in his twenties, that Galileo dedicated his Dialogue. In 1610 the Grand Duke's father had appointed Galileo "first mathematician and philosopher" at his court. Interested in science, Ferdinando II confirmed Galileo's position when he took power and granted permission to have the Dialogue printed in Florence. It may be that Galileo had his patron's influence to thank for the lenient judgment in the trial against the Dialogue.

Niccolò Riccardi (1585–1639)

Niccolò Riccardi was sent as a young man to Spain, where he joined the Dominican Order. When King Philip II heard him preach, he called him "monstrum" – it is not clear whether this was because of his enormous obesity or his eloquence – but in any case the name stayed with him ("Padre Mostro") for the rest of his life.

Riccardi acknowledged and praised Galileo's Saggiatore and finally granted permission for the introduction "To the discerning reader" to be added to the text.