In geometry, Hesse's principle of transfer (German : Übertragungsprinzip) states that if the points of the projective line P are depicted by a rational normal curve in P, then the group of the projective transformations of P that preserve the curve is isomorphic to the group of the projective transformations of P (this is a generalization of the original Hesse's principle, in a form suggested by Wilhelm Franz Meyer). It was originally introduced by Otto Hesse in 1866, in a more restricted form. It influenced Felix Klein in the development of the Erlangen program. Since its original conception, it was generalized by many mathematicians, including Klein, Fano, and Cartan.