<p>In this review, the history of cryptosporidiosis caused by parasites of the genus <i>Cryptosporidium</i> is outlined. These apicomplexan parasites evolved together with their vertebrate host during the early Cambrian period. The main etiological agents of human and bovine cryptosporidiosis are the zoonotic species <i>C. parvum</i> and the anthroponotic species <i>C. hominis</i>. Palaeoparasitological data indicate that humans have been parasitised by cryptosporidia since ancient times. Although the first <i>Cryptosporidium</i> species was described in 1907, the protozoan was only recognised as a gastrointestinal parasite of humans and cattle in the 1980s. The parasite became known to the general public primarily through media reports of waterborne outbreaks of gastroenteritis. Cryptosporidiosis is now acknowledged as a leading cause of diarrhoeal disease worldwide, with severe health implications for young, malnourished children and immunocompromised patients, and with severe economic consequences for cattle farmers.</p> Graphical Abstract <p></p>