Jehuda Halevi not only completely mastered the Hebrew language and the artistic forms of the neo-Hebraic poetry, but he also obtained a thorough knowledge of the Talmud, studied the natural sciences, penetrated even to the depths of metaphysics, and was skilled in all branches of learning. He wrote Arabic elegantly, and was conversant with the new-born Castilian poetry. He obtained a livelihood as a physician, practising medicine on his return to his native place. He appears to have been highly esteemed for his medical skill, for on one occasion he wrote to a friend that, living in a large town, he was busily engaged in the practice of his art. But, in spite of his constant care for the bodies of the sick and the dying, he did not forget his own soul, but ever maintained the ideals of his life. The following letter which, when advanced in years (about 1130), he wrote to a friend, is interesting: "I occupy myself in the hours which belong neither to the day nor to the night, with the vanity of medical science, although I am unable to heal. The city in which I dwell is large, the inhabitants are giants, but they are cruel rulers. Wherewith could I conciliate them better than by spending my days in curing their illness! I physic Babel, but it continues infirm. I cry to God that He may quickly send deliverance unto me, and give me freedom, to enjoy rest, that I may repair to some place of living knowledge, to the fountain of wisdom." The city of which Jehuda here speaks is Toledo, where he passed the years of his manhood. He longed, however, to depart thence, as Toledo had not yet become a center of Jewish learning. The whole power of his creative genius was bestowed upon the art of poetry and a thoughtful investigation of Judaism. He had a more correct conception of poetry, which he valued as something holy and God-given, than had his Arab and Jewish contemporaries. He distinctly enunciated the view that the faculty for composing poetry must be innate, original, not acquired. He mocked at those who laid down laws about meter and rhyme, and were very precise on those points. The truly inspired poet carries the laws within him, and will never be guilty of any blunders or inaccuracies. As long as he was young, he dissipated the gold of his rich poetry on light, flimsy themes, and following the example of others, wrote sparkling lyrics, in which he glorified his numerous friends. He sang of wine and pleasure, and composed riddles. When his friends rebuked him for this conduct (about 1110), he retorted in youthful insolence, "Shall one whose years scarce number twenty-four, Turn foe to pleasure and drink wine no more?"