“Today’s 52-card deck preserves the four original French suits of centuries ago:
clubs (♣), diamonds (♦), hearts (♥), and spades (♠)… Some historians have suggested that suits in a deck were meant to represent the four classes of Medieval society. Cups and chalices (modern hearts) might have stood for the clergy; swords (spades) for the nobility or the military; coins (diamonds) for the merchants; and batons (clubs) for peasants… The king of hearts, the only king without a mustache, appears to be killing himself by means of a sword to the head. The explanation for the ‘suicide-king’ is less dramatic. As printing spurred rapid reproduction of decks, the integrity of the original artwork declined. When printing blocks wore out, card makers would create new sets by copying either the blocks or the cards. This process amplified previous errors. Eventually, the far edge of our poor king’s sword disappeared.”

– Adrienne Bernhard,
The Lost Origins of Playing-Card Symbols, The Atlantic, Aug 24, 2017