Textbook descriptions of the foundations of Genetics give the impression that besides Mendel's no other research on heredity took place during the nineteenth century. However, the publication of the "Origin of Species" in 1859, and the criticism that it received, placed the study of heredity at the centre of biological thought. Consequently, Herbert Spencer, Charles Darwin himself, Francis Galton, William Keith Brooks, Carl von Nageli, August Weismann, and Hugo de Vries attempted to develop theories of heredity under an evolutionary perspective, and they were all influenced by each other in various ways. Nonetheless, only Nageli became aware of Mendel's experimental work; it has also been questioned whether Mendel even had the intention to develop a theory of heredity. In this article, a short presentation of these theories is made, based on the original writings. The major aim of this article is to suggest that Mendel was definitely not the only one studying heredity before 1900, if he even did this, as may be inferred by textbooks. Although his work had a major impact after 1900, it had no impact during the latter half of the nineteenth century when an active community of students of heredity emerged. Thus, textbooks should not only present the work of Mendel, but also provide a wider view of the actual history and a depiction of science as a social process.