Giuseppe Cesari
He apparently trained under Giuseppe Cesari d’Arpino. Baglione recounts that during the papacy of Sixtus V, Prospero was one of the many artists that decorated the Scala Sancta walls and ceilings with frescoes. He worked on the depiction of "Moses parting the Sea" and "Isaac blessing Jacob". In the benediction loggia of San Giovanni Laterano, he depicted an episode in the "Life of Constantine". He also worked painting in the Vatican libraries. He is described as an avid painter of Grotteseques. He also worked with Antonio Circignani to decorate a room in the Palazzo Antici-Mattei in Rome.