Too recently discovered to be included in this history is a 1940 paper of the Italian mathematician Bruno de Finetti, predating Markowitz and Roy by 12 years, which formulates mean-variance portfolio theory, including a justification for measuring risk by portfolio variance, the equation relating the covariances of security returns to the portfolio variance of return, mean-variance efficient sets, and a critical line algorithm to numerically solve the portfolio selection problem. Although de Finetti's paper formulates the general quadratic programming problem including short-sale constraints for the general case, only an algorithm for solving it in the special case of uncorrelated returns is fully worked out. Written in Italian, the paper has remained unknown among financial economists until it was just recently brought to my attention and translated into English.