Nicolaus Copernicus "Almagest" circa 150 CE; the Earth was the stationary center of the universe. Stars were embedded in a large outer sphere which rotated rapidly, approximately daily, while each of the planets, the Sun, and the Moon were embedded in their own, smaller spheres. Ptolemy's system employed devices, including epicycles, deferents and equants, to account for observations that the paths of these bodies differed from simple, circular orbits centered on the Earth. Copernicus' major work on his heliocentric theory was "Dē revolutionibus orbium coelestium" ("On the Revolutions of the Celestial Spheres"), published in the year of his death, 1543. He had
Bodhisattvas of the Earth more references to the Lotus Sutra in his commentaries than any other sutras. His commentaries focused primarily on the 15th (Emerging from the Earth) and 16th (Life Span) Chapters of the Lotus Sutra. Dōgen made numerous speculations about the significance of the bodhisattvas who emerged from the underground. As conceived by Dōgen, the stories of the underground bodhisattvas and the Buddha's inconceivable life-span serve as a fundamental shift in the development of East Asian Mahayana understanding of Buddhahood, an immediate attainment based on fundamental awakening rather than an achievement based on lifetimes of arduous practice. This can be conceived as