The heart shape (♥) is an ideograph used to express the idea of the "heart" in its metaphorical or symbolic sense as the center of emotion, including affection and love, especially (but not exclusively) romantic love.
The "wounded heart" indicating love sickness came to be depicted as a heart symbol pierced with an arrow (Cupid's), or heart symbol "broken" in two or more pieces.
The combination of the heart shape and its use within the heart metaphor developed at the end of the Middle Ages, although the shape has been used in many ancient epigraphy monuments and texts. With possible early examples or direct predecessors in the 13th to 14th century, the familiar symbol of the heart representing love developed in the 15th century, and became popular in Europe during the 16th. Before the 14th century, the heart shape was not associated with the meaning of the heart metaphor. The geometric shape itself is found in much earlier sources, but in such instances does not depict a heart, but typically foliage: in examples from antiquity fig leaves, and in medieval iconography and heraldry typically the leaves of ivy and of the water-lily.
The first known depiction of a heart as a symbol of romantic love dates to the 1250s. It occurs in a miniature decorating a capital 'S' in a manuscript of the French Roman de la poire (National Library FR MS. 2086, plate 12). In the miniature a kneeling lover (or more precisely, an allegory of the lover's "sweet gaze" or douz regart) offers his heart to a damsel. The heart here resembles a pine cone (held "upside down", the point facing upward), in accord with medieval anatomical descriptions. However, in this miniature what suggests a heart shape is only the result of a lover's finger superimposed on an object; the full shape outline of the object is partly hidden, and therefore unknown. Moreover, the French title of the manuscript that features the miniature translates into "Novel Of The Pear" in English. Thus the heart shaped object would be a pear; the conclusion that a pear represents a heart is dubious. Opinions therefore differ over this being the first depiction of a heart as symbol of romantic love.Giotto in his 1305 painting in the Scrovegni Chapel (Padua) shows an allegory of charity handing her heart to Christ, this heart is also depicted in the pine cone shape based on anatomical descriptions of the day (still held "upside down"). Giotto's painting exerted considerable influence on later painters, and the motive of Caritas offering a heart is shown by Taddeo Gaddi in Santa Croce, by Andrea Pisano on the bronze door of the south porch of the Baptisterium in Florence (c. 1337), by Ambrogio Lorenzetti in the Palazzo Publico in Siena (c. 1340) and by Andrea da Firenze in Santa Maria Novella in Florence (c. 1365). The convention of showing the heart point upward switches in the late 14th century and becomes rare in the first half of the 15th century.