Variational formulation of general relativity from 1915 to 1925 “Palatini's method” discovered by Einstein in 1925

Among the three basic variational approaches to general relativity, the metric-affine variational principle, according to which the metric and the affine connection are varied independently, is commonly known as the “Palatini method.” In this paper we revisit the history of the “golden age” of general relativity, through a discussion of the papers involving a variational formulation of the field problem. In particular we find that the original Palatini paper of 1919 was rather far from what is usually meant by “Palatini's method,” which was instead formulated, to our knowledge, by Einstein in 1925.