D O C U M E N T 4 1 7 O N G E N E R A L R E L A T I V I T Y 3 5 1 the terms you already approved.[4] I hope to arrange everything so that the majority of the whole work will be published over the course of the year. Scholars and admirers would like to confer upon you a chair at the University of Rome. With this in mind I was asked by many quarters for bibliographic and other information, which I also provided. I am now commissioned, under strict confiden- tiality, to find out whether you would be inclined to teach higher mathematics and theoretical physics and would you please have a statement sent out to me in this regard with indications as to whether and to what extent I may make use of it? I shall, in any case, treat it with the greatest discretion but can already assure you in advance that our wish, which is excellently supported, will be fulfilled, the more so as it meets strict scientific requirements. Requesting, if possible, a prompt reply, I again ask you please to accept this expression of my highest admiration. Respectfully, Rafaele Contu 417. “On the General Theory of Relativity” [On board SS Haruna Maru, ca. 9 January 1923][1] On the General Theory of Relativity. A. Einstein §1. Generalities The most powerful impulse Theoretical efforts of the past few years in the field of general relativity theory spring from correspond to two sources trains of thought. First, the aim was to comprehend the gravitational field and the electro- magnetic field under a single as a unified entity second, the splitting distinction of the concept of affine connections from the originally purely metric foundation of Riemannian geometry yielded new possibilities or, resp., limitations on the choice of equations to express natural laws. The basis of Riemannian geometry is the fundamental metric invariant , (1) from which all the theory’s other concepts are derived. Among these derived con- cepts, the parallel displacement of vectors which determines the affine connection is of primary interest to us here, determined according to the formula [p. 1] ds2 gμνdxμdxν =