Eleven years before the "rediscovery" in 1900 of Mendel's work, Hugo De Vries published his theory of heredity. He expected his theory to become a big success, but it was not well-received. To find supporting evidence for this theory De Vries started an extensive research program. Because of the parallels of his ideas with the Mendelian laws and because of his use of statistics, he became one of the rediscoverers. However, the Mendelian laws, which soon became the foundation of a new discipline of genetics, presented a problem. De Vries was the only one of the early Mendelians who had developed his own theory of heredity. His theory could not be brought in line with the Mendelian laws. But because his original theory was still very dear to him, something important was at stake and he was unwilling to adapt his ideas to the new situation. He belittled the importance of the Mendelian laws and ended up on the sidelines.