 He is best known for an account of a journey of lunar discovery, "Syzygies and Lunar Quadratures", which is credited as the first science fiction text written in the Americas.Little is known of Rivas's life outside of the trial for heresy; his birth and death dates are unknown, though it appears he was already an old man by the time he was brought to trial.According to Rivas scholar Miguel Ángel Fernández Delgado, he arrived in Yucatán in 1742, and soon started "making enemies and trouble for himself."