Considered to be one of the three greatest mathematicians in history. Known for constructing a regular 17-sided polygon with only a compass and ruler (this feat was never discovered since the Ancient Greeks, who knew only up to 15 sides), concluding that any polygon with the number of sides equal to a Fermat prime can be constructed, works in his Disquisitiones Arithmeticae on number theory, developed the modulus notation, discovered the fundamental theorem of algebra, calculated the orbit of Ceres, various works on electromagnetism and geodesy, invented the heliotrope, and other contributions too numerous to mention. Did not publish his thoughts on non-Euclidean geometry for fear of being rejected. Considered to be the last universalist before Poincare.