We may look upon Omar as a deeply learned man, following his own convictions, who, tortured with the question of existence, and finding no solution to life in Musulman dogmas, worked out for himself a regular conception of life based on Sufistic Mysticism; a man who, without discarding belief, smiled ironically at the inconsistencies and peculiarities of the Islam of his time, which left many minds dissatisfied in the fourth and fifth centuries, needing as it did vivification. It found this in the person of Ghazzali, who in this movement assigned the proper place to the Mystic element. Omar was a preacher of moral purity and of a contemplative life; one who loved his God and struggled to master the eternal, the good, and the beautiful. In this manner also is Omar portrayed in the various early biographical notices: a defender of «Greek Science,» famous for his knowledge of the Koran and the Law, and at the same time a «stinging serpent» to the dogmatic; a wit and a mocker, a bitter and implacable enemy of all hypocrisy; a man who, while curing others of the wounds of worldly triviality, impurity, and sinful vanity, himself only with almost his last breath closed the philosophic book on «Healing» and turned with a touching prayer to the One God, the Infinite, whom he had been striving to comprehend with all the strength of his mind and heart. Khayyam's lively protests and his heated words in freedom's cause brought upon him many bitter moments in his life and exposed him to numerous attacks at the hands of the mullahs, especially those of the Shiite community. Besides these, then as now (apart from hypocrites), persons were not wanting who, failing to understand Omar, regarded him as an unbeliever, atheist, and materialist. But in the course of centuries the people of Persia and India, realizing, perhaps instinctively, the injustice of former reproaches, have taken to publishing and reading Omar Khayyam in collections side by side with Abu-Said, Abd-Allah Ansari, and Attar--that is to say, with Sufi Mystics of the purest water, men whose moral and religious reputations were spotless. Rightly to understand Omar some knowledge of Sufism and its tenets is necessary. Sufism is a mystical doctrine which had its birth on the Arabian coast, and succeeded in implanting itself there to the point of putting a decisive check upon the orthodox philosophy. The etymology of the name is difficult to find. According to some, it comes from the word _suf_ (wool, a woolen garment) because the first persons to adopt this doctrine clothed themselves in wool.