While examining T. S. Eliot’s experiment in his apprentice poems written in his adolescent years but not published in his life time, this article investigates the ways in which he trained himself to find his own distinctive voice and realize the essential characteristics of modern poetry in his early poetic works. The young Eliot had a strong sense of the tradition of English poetry as well as self-restraint that his familial and educational culture imposed on him, but he had also an intense desire to create a new poetry in the real-life modern language. Reading the great authors as well as minor authors, and “borrow[ing] the best verse of other languages and the best prose of all languages,” he modified vigorously the various poetic forms and contents and fused them together, and succeeded in modernizing his poems. He called his own poetic experiment a “cross,” that he borrowed from Samuel Butler’s Life and Habit. When he mastered entirely the diverse poetic techniques in his early poems, he became able to speak in his own voice and lay a solid foundation for his later works such as The Waste Land and Four Quartets.