He took part in the conclave of 1667, that of 1669–1670, that of 1676, that of 1689 and finally that of 1691; during the latter he was among the principal papabili, but his election was blocked by the Spaniards who did not see favorably a Venetian on the papal throne.[2]
Parnaso del'Em.mo Cardinal Delfino. Utrecht: Willem Kroon, 1730
Delfino's literary activity begun in his university years in Padua. Today he is chiefly remembered for his four plays. He wrote three historical tragedies based on the traditional Counter-Reformation conflict between reason of state and love or personal ethics: Cleopatra, Lucrezia, Creso; and a free adaptation from the Orlando Furioso, Medoro, all printed posthumously.[4] Delfino contributed to the controversy over the propriety of rhyme in tragedy, and himself used less rhyme in his later works.
Although well known and appreciated in intellectually distinguished circles, Delfino chose not to publish his works during his lifetime. The Cleopatra was first printed in Scipione Maffei's collection Teatro italiano. The four tragedies were published in Utrecht in 1730 and re-edited in a much more correct edition by Comino in Padua in 1733 together with an apologetic Dialogo sopra le tragedie, in which he advocated a neoclassical reform of tragedy.[5]
Delfino wrote six Dialogues in verse on philosophical and scientific questions that were published posthumously in Venice in 1740.[6] He left two manuscripts containing ten philosophical and scientific Dialogues in prose. Delfino appears to be very well versed in the New Science, discusses Pierre Gassendi’s and Galileo’s theories, Lucretius' atomism, the philosophy of Franciscus Patricius and Francis Bacon and the scientific and philosophical ideas of Fortunio Liceti and Athanasius Kircher.[7] His vivid writing style was much appreciated by Orazio Rucellai and Carlo Roberto Dati.[7] Only one of his prose Dialogues - dedicated to astronomy - has been published.[2]
He wrote also poems on celebratory, heroic or meditative subjects and ethical and political remarks on Sallust's Bellum Catilinae and Tacitus's Agricola.
B. CHIURLO, I manoscritti letterari del patriarca Giovanni Delfino, «Archivio veneto», s. 5, XXIV (1939), 121-71;
F. ANSELMO, Giovanni Delfino tra classico e barocco, Messina, 1962.
D. DELLA VALLE, Il neostoicismo in una tragedia barocca italiana. La Cleopatra del cardinal Delfino, in La frattura. Studi sul barocco letterario francese, Ravenna, 1970, 306-17;
M. SARNELLI, «Ed a me piacque sempre / filosofar con libertà...» i sei dialoghi filosofico-scientifici in poesia di Giovanni Delfino, «Philo(:)logica», IV/7 (1995), 66-89 and 8, 96-118;
SARNELLI, M. (1996). ""Maravigliosa chiarezza", "raccomandazioni" e "mal di pietra": il carteggio Delfino-Pers". Studi secenteschi. 37: 225–315.
TADDEO, E. (1999). "Torcigliani e Delfino, patriarca atomista". Studi secenteschi. 40: 83–95.
Bigi, Stefano (2002). "Letteratura e scienza gli inediti dialoghi in prosa di Giovanni Delfino (1617-1699)". Aevum. 76 (3): 775–827. ISBN978-3110673470. JSTOR20861380.
Sarnelli, Mauro (2020). "Lucretius in (moderate) Baroque: Meanings and Functions of the Lucretian Auctoritas in Giovanni Delfino's Philosophical and Scientific Dialogues in Prose". Lucretius Poet and Philosopher. De Gruyter: 251–271. doi:10.1515/9783110673487-014. ISBN978-3110673470. S2CID242896158.