Geometry Unified

With the unification of geometries as the center, with the establishment, development and confirmation of projective geometry and non-Euclidean geometry as the main concern, with the high priest and their relevant work as the clue, and on the basis of the work of the older generation and abundant materials, the present paper summarizes the development of geometries from the end of the 18th century to the beginning of the seventies of the 19th century(the unification of geometries by means of group)systematically, analyzes the historical background and ideological roots briefly, and proves that the unification of geometries is the result of the historical development and the irresistible natural law.