In the late 1880s, Mehnert, performing a systematic study of ‘angiosclerosis’, found the internal carotid artery commonly affected; a few years later, Chiari identified it as a source of thrombo-embolism to the brain. Yet, throughout the first half of the twentieth century, the role of the extracranial arteries remained underestimated, for two reasons: the presence of communicating arteries and the ‘concealed’ location of the neck arteries, between the brain arteries and known sources of embolism. Primary atherothrombosis of intracerebral arteries was commonly assumed, even though arteries supplying a softened area could be found patent and intact (Foix and Ley).