There are two main difficulties confronting the historian, when he attempts to write history. He must always ask himself, First: Are the facts which I find recorded really facts, and Second: Do I interpret them correctly? Thiers, in his “Histoire du Consulat,” Paris, 1851, Vol. XI, p. 71, speaks of the enthusiasm with which the Jews of Portugal, who numbered 200,000, received the French troops in 1809. There were perhaps not two hundred Jews living in Portugal at that time, and they played no part in public affairs. In an address to the convention of the Order Brith Abraham, Mayor Gaynor, of New York, said on May 15, 1910: “The great Frederick issued a general privilege, and declared it as a maxim, that oppression of the Jews never brought prosperity to any state, and Napoleon not only followed the same course but convoked the Sanhedrin.” The facts are in the main correct, but the presentation is all wrong. Frederick issued his “Revidierte Generalprivilegium” of April 17, 1750, for the Jews of Prussia, but it is based on the mediæval idea of restrictions in the most elementary rights of human beings. His sentiment with regard to the Jews is evident from a letter which he wrote to the Minister von Hoym, May 17, 1780, in which he says: “If the Jews were expelled and Christians would take their places as innkeepers, it would be for the good of the country, and we would have more human beings and less Jews” (_Monatsschrift fuer die Geschichte und Wissenschaft des Judentums_, 1895, p. 379). Napoleon had by the convocation of the “Assembly of Jewish Notables” and the subsequent Sanhedrin, 1806-1807, insulted the Jews. The law of September 27, 1791, had declared them as citizens, and he asked them whether they considered France as their fatherland, and when these and similar questions were answered in the affirmative with emphatic protestation of loyalty, Napoleon nevertheless reintroduced the mediæval principle of Jewish disabilities by issuing laws restricting Jews in doing business on credit. The facts quoted by Mayor Gaynor prove the opposite of what he wished to prove by them. These instances taken from Jewish history could be multiplied endlessly from every period and every section of the world’s history. Jewish history has to contend with two additional difficulties. It extends over every part of the civilized world, but it lacks chronological sequence, at least until we come to modern times. Another difficulty is that it deals with almost every known spiritual activity of mankind. The student, in order to understand Jewish history, should know the constantly shifting boundary lines of the Italian states from mediæval times until 1870, and he should know something of the morphological theories of Hebrew grammar and of scholastic philosophy.