ABSTRACT
This paper is a survey of one aspect of Leibniz's diplomatic and scientific activities, namely, his attempts to have the ban on the Copernican system abolished. The ban was issued by the Congregation of the Index (instituted by Pius V in 1571) in 1616, more than seventy years after the publication of Copernicus' De revoll4tionibus orbium coelestium; thus, the censorship was imposed by a congregation of cardinals, and the Copernican system was not formally declared heretical by the Pope. In 1620 the ban on the book was lifted, provided a few passages were crossed out, and the whole work appeared as an astronomical hypothesis. Bur it was only in 1757 that Benedict XIV rescinded the anticopernican decree. Galilei's Dia/ogo sopra i due massimi sistemi del mondo, however, was removed from the index of prohibited books only in 1835.
