"W.H. Auden once argued that the standard for recognizing a major poet should be established by the following points: 1. A large body of work; 2. A wide range of subject matter and treatment; 3. An unmistakable originality of vision and style; 4. A mastery of technique; 5. A constant, progressive process of maturation--so that should an authors individual works be placed side by side at any stage of his or her career, it would always be clear which work came first and which came after. "
Found in this article.