were at the time rampant and fashionable, and faith in immortality was at a low ebb. At this favourable juncture appeared Phädon oder über die Unsterblichkeit der Seele (Phaedo or On the Immortality of Souls; 1767). Modelled on Plato's dialogue of the same name, Mendelssohn's work possessed some of the charm of its Greek exemplar and impressed the German world with its beauty and lucidity of style. Phaedo was an immediate success, and besides being one of the most widely read books of its time in German was speedily translated into several European languages, including English. The author was hailed as the "German Plato", or the "German Socrates"; royal and other aristocratic friends showered attentions on him, and it was said that "no stranger who came to Berlin failed to pay his personal respects to the German Socrates." Lavater So far, Mendelssohn had devoted his talents to philosophy and criticism; now, however, an incident turned the current of his life in the direction of the cause of Judaism. In April 1763, Johann Kaspar Lavater, then a young theology-student from Zurich, made a trip to Berlin, where he visited the already famous Jewish philosopher with some companions. They insisted on Mendelssohn telling them his views on Jesus and managed to get from him the statement, that, provided the historical Jesus had kept himself and his theology strictly within limits of orthodox Judaism, Mendelssohn "respected the morality of Jesus' character." Six years later, in October 1769, Lavater sent Mendelssohn his German translation of Charles Bonnet's essay on Christian Evidences, with a preface where he publicly challenged Mendelssohn to refute Bonnet or if he could not then to "do what wisdom, the love of truth and honesty must bid him, what a Socrates would have done if he had read the book and found it unanswerable." Mendelssohn answered in an open letter in December 1769: "Suppose there were living among my contemporaries a Confucius or a Solon, I could, according to the principles of my faith, love and admire the great man without falling into the ridiculous idea that I must convert a Solon or a Confucius." The ongoing public controversy cost Mendelssohn much time, energy and strength. Lavater later described Mendelssohn in his book on physiognomy, Physiognomische Fragmente zur Beförderung der Menschenkenntnis und Menschenliebe (1775–1778), as "a companionable, brilliant soul, with piercing eyes, the body of an Aesop [who was traditionally considered