During the 1890s several biologists began doing experiments on breeding. and soon Mendel's results were duplicated, even before his papers were read. Carl Correns and Hugo de Vries were the main rediscoverers of Mendel's writings and laws. Both acknowledged Mendel's priority, although it is probable that de Vries did not understand his own results until after reading Mendel. Though Erich von Tschermak was originally also credited with rediscovery, this is no longer accepted because he did not understand Mendel's laws. Though de Vries later lost interest in Mendelism, other biologists built genetics into a science.