When discussing the heart’s figuration in medieval and early modern European visual culture, scholars have chiefly addressed its shape and how it was held, but there is remarkably little discussion of the heart radiating flames or depicted over a fire.1 The heart, and then the flaming heart, became a visual attribute of several sacred figures (most notably Christ, Mary, and St. Augustine) as well as the allegorical personifications of Charity and of secular Amore and Venus. Such cardiac symbols suggest the fiery, ardent emotional intensity of divine suffering and love, or of secular desire, with the heart being a common metaphor for a person’s central character and core emotions (the Latin for heart being cor). But what is the impulse for these fiery hearts? Rather than a natural and transparent signifier of passion, as is so often assumed, the burning heart emerges slowly in European visual culture and my chapter briefly traces that iconographic history in relation to the intellectual and experiential contexts of medical beliefs, religious symbolism, and amorous poetry (both sacred and secular). Such an overview ensures that in any particular case study, visual or otherwise, the personal and individual can be understood in relation to the bigger picture of conventional and contextual patterns, and claims for historical change can be measured against those broader intellectual, cultural, and social trends. Furthermore, fundamental ideas about the heart as a physical organ were closely interwoven with its metaphorical and visual dimensions.
Medical Theories
Valentine’s Day imagery, popular culture, and numerous emoticons show that we are still heirs to a principle underlying ancient ideas about the body, that the heart was the principal organ, site of life force as well as emotions. For centuries, Europeans adopted the ancient physiological scheme that believed human bodies were regulated by various humors, and that an imbalance caused disease and emotional excess.2 But little has been said about anatomical theory concerning the heart’s function, which was another inheritance from the classical world that also shaped ideas about the intertwining of corporeality with emotions. Contrary to what is commonly assumed by scholars studying the modern era, the heart was the center of human emotions millennia before the seventeenth century. Over the course of that century, a host of shifts in the efficacy and intensity of emotional imagery incorporated the flaming heart, but it was far from a novel symbol when authors like William Harvey, René Descartes, and Robert Burton wrote of the fiery heart.
Plato’s blend of physical evidence, medical theory, teleological reasoning, and natural philosophy influentially established a basic association between the heated heart and emotions. Around 360 BCE, he explained that the gods placed reason in the head and soul in the thorax. That part of the soul “which partakes of courage and spirit, since it is a lover of victory” was closer to the head, between the midriff and the neck, thereby more able to be ruled by reason, which could “forcibly subdue the tribe of the desires” when they were disobedient. The heart was “the chamber of the bodyguard, to the end that when the heat of the passion boils up” reason would instead prevail throughout the body. He relied on commonly understood medical ideas to then say that respiration of the lungs provided relief for heated passions, cooling “the leaping of the heart, in times when dangers are expected and passion is excited – since [the gods] knew that all such swelling of the passionate parts would arise from the action of fire.”3
Ancient Greek medical theory established that the heart was the body’s primary organ and that innate heat was its most basic distinguishing feature and function.4 Aristotle believed that the seat of consciousness resided in the heart rather than the brain proposed by Plato and it was the source of both emotions and motion.5 He instructed that the heart “is necessary because there must be a source of heat: there must be, as it were, a hearth, where that which kindles the whole organism shall reside; and this part must be well guarded, being as it were the citadel (akropolis) of the body.”6
Galen later disagreed with some of Aristotle’s conclusions and was less influential in medieval curricula, though the works of this second-century CE physician, who wrote in Greek, underwent a revival during the Renaissance once improved translations were available. For him too, the heart was the source of the body’s crucial, innate heat and was the organ most closely related to the soul.7 He reiterated metaphors about the organ’s primacy, likening it to a furnace or hearth: “The heart is, as it were, the hearthstone and source of the innate heat by which the animal is governed.”8
Medieval anatomical texts reiterated the principle that the heart was the most important “spiritual member” and an engine of heat, generating “vital spirits and blood” that gave the entire body “heat and life.”9 The twelfth-century Anatomia attributed to Master Nicholas explained that the heart was “hot in complexion” and “hollow, to provide for ebullition of the blood and generation of the vital spirits.”10 Never described in detail, the heart’s process of bubbling, refining, thinning, vaporizing, or purifying blood was usually situated in the right ventricle, while in the left chamber it was aerated, mixed or cooled with pneuma or spirit chiefly drawn from the lungs. The essential heating function of the heart was still a basic principle to Descartes, who wrote in 1649 that blood “carries the heat it acquires in the heart to all the other parts of the body, and serves as their nourishment.”11 Decades after Harvey’s publication in 1628 of his discovery that the blood circulates through the body by means of the pumping action of the heart, Descartes continued to adhere closely to ideas first propounded in ancient medicine.
Visual culture confirmed the standard model of the heart. Plato’s notion of an upper and lower division of the torso is still clearly represented in the woodcut of Gregor Reisch’s encyclopedic compendium Margarita philosophica, first published in Freiburg in 1503, where the heart, surrounded by the lungs, is separated from the lower spleen, liver, intestines, and other organs.12 The heart’s purpose in relation to life and heat is remembered in Piero di Cosimo’s panel of the 1510s depicting Prometheus bringing fire to humanity, holding his torch up to the cardiac region of the lifeless figure’s chest so that it will be animated by the spark of soul, passion and life.13
Emotions remained associated with the heart. The ca. 1225 Anatomia vivorum refuted the claim that boldness was due to a large heart (think of “Richard the Lionheart”), fear and timidity to a small organ, nevertheless opining that the boldest animals “have both large hearts and much heat.”14 The medical plotting of astrological influences on the body of Zodiac Man thus had the sign of Leo associated with the heart.15 Others held Aristotle’s opposite view, that “animals whose heart is large are timorous, and those with a small or smaller heart are more bold and confident.”16 In either case, the heart was the physical seat of emotions. Considering issues of causation and corporeality in relation to the heart, in the thirteenth century Thomas Aquinas argued that the passions of the soul move the physical heart, giving examples such as rage inflaming its blood, whereas most ancient authorities proposed that the emotional state of anger was caused by overheated blood.17
Observable physical changes like the red face of an angry person or the faster pulse when someone was afraid or excited, helped to construct, then sustain the link between the heart and emotions. The pulse was considered indicative of many “fluctuations of the mind...
