Wegener originated the theory of continental drift in this paper on the origin of continents, which he conceived after being struck by the apparent correspondence in the shapes of the coastlines on the west and east sides of the Atlantic, and supported with extensive research on the geological and paleontological correspondences between the two sides. He postulated that 200 million years ago there existed a supercontinent (“Pangaea”), which began to break up during the Mesozoic era due to the cumulative effects of the “Eötvös force,” which drives continents towards the equator, and the tidal attraction of the sun and moon, which drags the earth’s crust westward with respect to its interior. Wegener’s theory attracted little interest until 1919, when he published the second edition of his treatise Die Entstehung der Kontinente und Ozeane.