Eduard von Keyserling belonged to a Baltic-German family that had been in Courland--which at the time of Keyserling's birth in 1855 was the central Baltic province of the czarist empire, with Livonia to the south and Estonia to the north--since the fifteenth century. Originally from Westphalia, the Keyserlings had become "vassals" of the Teutonic Knights, and then had been active in Russian and Prussian military and diplomatic service, all the while maintaining their family estates. One forebear, Dietrich von Keyserling, was the confidant of the young Frederick, later to be called "the Great." As crown prince, Frederick gave Dietrich the sobriquet Caesarion (Keyserling can be taken to mean "little Caesar") and described him to Voltaire in these words: "Caesarion a le malheur d'être né Courlandois, mais il est le Plutarque de cette Beotie moderne" (Caesarion has the misfortune of being born a Courlander, but he is...