scanty earnings he bought a Latin copy of John Locke's An Essay Concerning Human Understanding, and mastered it with the aid of a Latin dictionary. He then made the acquaintance of Aaron Solomon Gumperz, who taught him basic French and English. In 1750, a wealthy Jewish silk-merchant, Isaac Bernhard, appointed him to teach his children. Mendelssohn soon won the confidence of Bernhard, who made the young student successively his bookkeeper and his partner. It was possibly Gumperz who introduced Mendelssohn to Gotthold Ephraim Lessing in 1754, who became one of his greatest friends. It is said that the first time Mendelssohn met Lessing, they played chess. In Lessing's play Nathan the Wise Nathan and the character Saladin first meet during a game of chess. Lessing had recently produced the drama Die Juden, whose moral was that a Jew can possess nobility of character. This notion was, in the contemporary Berlin of Frederick the Great, generally ridiculed as untrue. Lessing found in Mendelssohn the realization of his dream. Within a few months, the two became closely intellectually allied. Lessing also brought Mendelssohn to public attention for the first time: Mendelssohn had written an essay attacking Germans' neglect of their native philosophers (principally Gottfried Leibniz), and lent the manuscript to Lessing. Without consulting the author, Lessing published Mendelssohn's Philosophical Conversations (Philosophische Gespräche) anonymously in 1755. In the same year there appeared in Danzig (now Gdańsk, Poland) an anonymous satire, Pope a Metaphysician (Pope ein Metaphysiker), which turned out to be the joint work of Lessing and Mendelssohn. Early prominence as philosopher and critic Mendelssohn became (1756–1759) the leading spirit of Friedrich Nicolai's important literary undertakings, the Bibliothek and the Literaturbriefe, and ran some risk (which Frederick's good nature mitigated) by criticizing the poems of the King of Prussia. In 1762 he married Fromet Guggenheim, who survived him by twenty-six years. In the year following his marriage Mendelssohn won the prize offered by the Berlin Academy for an essay on the application of mathematical proofs to metaphysics, On Evidence in the Metaphysical Sciences; among the competitors were Thomas Abbt and Immanuel Kant, who came second. In October 1763 the king granted Mendelssohn, but not his wife or children, the privilege of Protected Jew (Schutzjude), which assured his right to undisturbed residence in Berlin. As a result of his correspondence with Abbt, Mendelssohn resolved to write on the immortality of the soul. Materialistic views