De revolutionibus orbium coelestium have begun work on his new system by that time. Most historians believe that he wrote the "Commentariolus" after his return from Italy, possibly only after 1510. At this time, Copernicus anticipated that he could reconcile the motion of the Earth with the perceived motions of the planets easily, with fewer motions than were necessary in the "Alfonsine Tables", the version of the Ptolemaic system current at the time. In particular, the heliocentric Copernican model made use of the Urdi Lemma developed in the 13th century by Mu'ayyad al-Din al-'Urdi, the first of the Maragha astronomers to develop a non-Ptolemaic
Gardens of the Sun Brazil attempted to return most of the planet to a "natural" state, to the extent that most of Earth's population inhabits a few megacities. The Outers, by contrast, survive by terraforming the moons of Jupiter and the other outer planets and practicing genetic engineering, which caused ideological tension with Greater Brazil, ultimately flaring into a full-scale conflict called the "Quiet War". By the time of "Gardens of the Sun", the war is over. The surviving Outers have been forced to Uranus, Neptune and Pluto as the superpowers of Earth raid the moons of Jupiter and Saturn for Outer knowledge. However,