Paolo Sarpi (14 August 1552 15 January 1623) was a Venetian historian, prelate, scientist, canon lawyer, and statesman active on behalf of the Venetian Republic during the period of its successful defiance of the papal interdict (16051607) and its war (16151617) with Austria over the Uskok pirates. His writings, frankly polemical and highly critical of the Catholic Church and its Scholastic tradition, "inspired both Hobbes and Edward Gibbon in their own historical debunkings of priestcraft." Sarpi's major work, the History of the Council of Trent (1619), was published in London in 1619; other works: a History of Ecclesiastical Benefices, History of the Interdict and his Supplement to the History of the Uskoks, appeared posthumously. Organized around single topics, they are early examples of the genre of the historical monograph.As a defender of the liberties of Republican Venice and proponent of the separation of Church and state, Sarpi attained fame as a hero of republicanism and free thought and possible crypto Protestant. His last words, "Esto perpetua" ("may she [i.e., the republic] live forever"), were recalled by John Adams in 1820 in a letter to Thomas Jefferson, when Adams "wished 'as devoutly as Father Paul for the preservation of our vast American empire and our free institutions', as Sarpi had wished for the preservation of Venice and its institutions."Sarpi was also an experimental scientist, a proponent of the Copernican system, a friend and patron of Galileo Galilei, and a keen follower of the latest research on anatomy, astronomy, and ballistics at the University of Padua. His extensive network of correspondents included Francis Bacon and William Harvey.

Sarpi believed that government institutions should rescind their censorship of the Avvisithe newsletters that started to be common in his timeand instead of censorship, publish their own versions of the news to counter enemy publications. In that spirit, Sarpi himself published several pamphlets in defense of Venice's rights over the Adriatic. As such, Sarpi could be considered as an early advocate of the freedom of the press, though the concept did not yet exist in his lifetime.

Pope Paul V (Latin: Paulus V; Italian: Paolo V) (17 September 1550 – 28 January 1621), born Camillo Borghese, was head of the Catholic Church and ruler of the Papal States from 16 May 1605 to his death. In 1611, he honored Galileo Galilei as a member of the Papal Accademia dei Lincei and supported his discoveries. In 1616, Pope Paul V instructed Cardinal Bellarmine to inform Galileo that the Copernican theory could not be taught as fact, but Bellarmine's certificate allowed Galileo to continue his studies in search for evidence and use the geocentric model as a theoretical device. That same year Paul V assured Galileo that he was safe from persecution so long as he, the Pope, should live. Bellarmine's certificate was used by Galileo for his defense at the trial of 1633.