PLATONIC Year, or the Great Year, is a period of time determined by the revolution of the equinoxes, or the space wherein the stars and constellations return to their former places in respect of the equinoxes. The platonic year, according to Tycho Brahe, is 25816, according to Ricciolus 25910, and according to Cassini 24800 years.
This period once accomplished, it was an opinion among the ancients that the world was to begin anew, and the same series of things to turn over again.