The first patients with xanthomatosis and cardiovascular disease were described in end of the 18th century. From 1925 to 1938, the Norwegian pathologist Francis Harbitz (1867-1950) published several reports on sudden death and xanthomatosis. Harbitz called attention to certain peculiarities of the xanthomatosis. Microscopically he found that the so-called foam cells are more marked and more characteristic than in senile arteriosclerosis. Carl Müller's (1886-1983) attention was directed to this form of cardiovascular disease by the publications of Harbitz. Based on his own studies of 17 families in Oslo over a short period from 1936, he published his final report in 1939. He described hereditary heart disease due to xanthomatosis and hypercholesterolaemia to be fairly common. It was demonstrated to be a dominant trait in the families. Hypercholesterolaemia was present, most marked in connection with xanthoma tuberosus, but there was no definitive relationship between hypercholesterolaemia and xanthomatous deposits in the skin. The occurrence of heart disease in families should direct attention to this disorder. Carl Müller postulated that causal and prophylactic treatment might prove to be of value, but more than 50 years passed before this was possible in the disorder that is now called familial hypercholesterolaemia.