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The physicians of the Alexandrine school seem to have been able to follow the way of the optic nerves from the retina to the brain. It was very probable that they should discover the thalamus. Sadly, anatomic knowledge, deriving from the first scientific human dissection performed in history, was destroyed in the fire of the Alexandrine Library. When, in the second century A.D., Galen introduced the term thalamus opticus, he was describing the central part of the lateral ventricles of the brain. After Galen, an anatomy with philosophical inferences substituted an anatomy based on direct observation. At that time the purpose was to find the site of the soul. During the thirteen centuries following Galen, including the Byzantine epoch and the High Middle Ages, the knowledge of the anatomy of the central nervous system did not make any substantial progress. The deep location of the thalamus contributed, for a very long time, to make it invisible to the eyes of the anatomists. It was Mondino da Luzzi, during the thirteenth century A.D., who gave the first incontestable description of the thalamus. He named the thalamus anchae (buttocks). Nevertheless, we should also consider the hypothesis that Galen, from whom Mondino always got his inspiration, could already have used the Latin term nates to name the pulvinar of the thalamus. Three centuries later, Andreas Vesalius, the true father of modern anatomy, first illustrated the thalamus in his artwork De humani corporis fabrica (1543). The thalamus was perfectly represented by Vesalio. He provided figures of the thalamus with accurate legends in many brain sections with different perspectives but, strangely, he did not mention it in the text. In the seventeenth century, Jean Riolan and Thomas Willis inaugurated the use of the term "thalamus" in its actual meaning, probably as a consequence of an inaccurate interpretation or the transcription of Galen's writings. The thalamus has superbly been represented by Willis and Vieussens in their De CerebriAnatome (1664) and Neuronographia Universalis (1684). These works were the first monographs of the human history to be integrally devoted to the central nervous system. During the eighteenth century the anatomic illustration began to conform itself more to a scientific than an artistic approach. Nevertheless, despite the presence of the thalamus in most atlases, only little scientific progress was made in its understanding. During that century,Alexander Monro (Monro Primus, 1697-1767) described the hypothalamic sulcus and the interventricular foramens clarifying their topography with the thalamic walls. Giovanni Domenico Santorini (1681-1737) accurately reported the link between the optic tracts and the structure he first named as the lateral geniculate body of the thalamus. Francois Pourfour du Petit (1664-1741), Santorini and then Felix Vicq d'Azyr (1748-1794) described the mammillothalamic tract. The modern approach to thalamic morphology began with the improving of the microscopy and histology techniques. In this context, K. F. Burdach proposed to separate the thalamus into distinct nuclei (1823) and later Jean Luys established the link between this anatomic subdivision and the idea of a functional specialisation (1865). Since then, a great amount of, often imprecise or contradictory, anatomic-functional data has accumulated rapidly.