From the fourteenth to the seventeenth centuries, widespread attention was paid to the heart and blood in courtly love, mysticism, alchemy, prose, and poetry. In the Aristotelian tradition, the heart was also considered as a mediator between soul and body. The anatomy and function of the heart were very important to Descartes from the Treatise on Man to his last work on the Passions of the Soul. The anatomical heart of three dimensions appeared late on the stage of medical knowledge. During the sixteenth century, Vesalius, Fabricius of Aquapendente, and Cesalpino investigated the heart and the motion of the blood, but no undisputed results followed from their endeavors. Columbus and Servetus described the lesser transit of venous blood through the lungs but necessarily stopped short of understanding the systemic circulation of the blood. The pulmonary and systemic circulations are part of the total circulation and only intelligible from William Harvey's later decisive viewpoints (Pagel 1967, Bitbol-Hespériès 1990, Van Hoorn 2011).

In Harvey's epoch-making On the Motion of the Heart and Blood (1628), the total one-way circulation of the blood is related to the extraordinary position and purpose of the heart. Using the well-known analogy of macro-microcosm, Harvey (1628, 42) states: “The heart is the beginning of life; the sun of the microcosm, even as the sun in his turn might well be designated the heart of the world.” In short, contrary to Galen, it is the swift contractions of the left chamber that spout nutrient blood into the aorta from where the various parts of the body are quickened and alimented.

We now turn to the relationship between Harvey and Descartes on matters of the heart. From the end of the 1620s, Descartes was reading and experimenting in anatomy. Mersenne was abreast of what Descartes was doing and discussed Harvey's publication with him. No later than 1632 he had read it and accepted Harvey's discovery of blood circulation. But he stuck to his own interpretations of the motion of the heart.