Art was always a popular subject for the Vatican's commemorative stamps, probably because the Vatican possesses the finest collections in the world. During John Paul II's reign, however, pre-Christian art came to the fore with issues depicting Greek, Etruscan, and Roman vases and busts (1983), Roman mosaics (1987), and treasures of the Gregorian Egyptian Museum (1989). Similar subjects appeared for the 2000th birth anniversary of the Roman poet Virgil and Raphael's painting The School Of Athens, which depicts great ancient philosophers, including Plato, Aristotle, and Socrates.
The church's contributions to and uses of science were also explored philatelically for the first time. In this vein are issues celebrating the equipment and astronomers of the Vatican's famous observatory (1979 and 1991); shortwave radio (1981); Pope Gregory the Great's use of mathematics and astronomy to reform the calendar (1982); and Fr. Gregor Mendel, the Augustinian priest known as the father of genetic theory (1984).