The Three of Swords is among the most recognisable cards in the modern deck, a heart pierced by three blades under rain, and it is one of the clearest cases where the image can be traced to a specific earlier source rather than to tradition.
The Sola Busca deck, engraved in Italy in the 1490s, is the only substantially surviving fifteenth-century pack with fully illustrated numbered cards. Photographs of it were acquired by the British Museum in the first decade of the twentieth century, shortly before Pamela Colman Smith began work, and several of her minor cards resemble Sola Busca compositions closely enough that the borrowing is generally accepted by historians of the deck. This card is among the examples usually cited.
The Marseille-pattern Three of Swords is three swords, arranged decoratively, with no heart, no rain and no scene. Everything that makes the modern card devastating was added in 1909.
That does not make the card less useful. A reader working with a scenic deck has an image of grief that communicates instantly, which is exactly what Smith was hired to produce. But the common claim that this card has always meant heartbreak confuses a picture drawn in 1909 with a meaning transmitted from the Renaissance.
Read as it stands, the card is grief with a cause: separation, betrayal, a truth that hurt, or the pain that follows clarity. Its most useful feature is its bluntness. It does not soften anything, and querents generally recognise it without being told.