The Old and the New Rome: Francesco Bianchini’s astronomical exchanges with the court of Lisbon

Abstract

In the 1720s a patronage relationship developed between King João V (1689-1750) of Portugal and the Italian astronomer Francesco Bianchini (1662-1729). This was hardly surprising in a time when Portuguese diplomatic and cultural relations with Rome were so intense. Dom João V ambitioned to be treated by the papacy on a par with Spanish and French kings who held the titles Rex Catholicissimus and Rex Christianissimus. Bianchini dedicated his opus magnum, the book Hesperi et Phosphori (Rome, 1728), to the Portuguese monarch, the generous patron of the opulent volume. In this work the Veronese presented detailed observations of the planet Venus and the cartography of spots he saw on its apparent face. Bianchini labeled those features honoring Portuguese and Italian historical figures. The dedication, inscribing the glory and power of the Portuguese king in the heavens, is to be seen in the context of the preceding cases of Galileo, with his four Medician Stars, and of Giovanni Domenico Cassini‘s discovery of four moons of Saturn, dedicated to Louis XIV. If to Dom João V this patronage was part of an effort to enhance status and prestige of the Portuguese monarchy in Europe, in particular within the catholic world, to Bianchini it meant an opportunity to accomplish and communicate more efficiently his astronomical discoveries.