If you are like me, I thought nothing of the Kings on playing cards and whether they represented real kings of past. I just thought they were just well-drawn pieces of art. It was to my surprise and interest that each king in a pack of playing cards represent famous kings in history. According to the International Playing Card Society, in France, they once depicted some of the most famous leaders in history.
Spades – King David
Clubs – Alexander the Great
Hearts – Charlemagne
Diamonds – Julius Caesar.
History of the King on Playing Cards
Playing cards arrived in Europe in the late 14th century, and decks differed greatly depending on where they were produced. There were inconsistent numbers of cards and design, although all decks had suits made up of court cards (now usually called face cards) and numbered cards. Depending on where they were created the design on the picture cards were diferent and their representation differed. As card playing became more and more popular , card makers eventually standardised the decks to include 52 cards, the same number a deck includes now.
It was the French card-makers in the late 16th century who standardized the suits of spades, hearts, diamonds, and clubs and designated the four kings as David, Alexander, Charlemagne, and Julius Caesar.
The Suicide King
The king of hearts is sometimes called the Suicide King because the sword he holds behind his head might be visualized as being used to stab himself in the head. This design evolved from earlier designs where he was holding a battle ax, but over the course of copies being made, the ax head was omitted, and the weapon changed to a curiously positioned sword.

Additional Playing Card Historical Personage:
Queen of Hearts = Judith (of the Book of Judith, an Apocryphal Book of the Bible).
Jack of Hearts = “La Hire,” a famous French warrior a.k.a. Etienne de Vignoles.
Queen of Spades = Pallas, a.k.a. Minerva.
Jack of Spades = Hogier the Dane, one of Charlemagne’s paladins.
Queen of Diamonds = Rachel (of the Bible).
Jack of Diamonds = Hector of Troy, or alternately, Roland of France.
Queen of Clubs = Argine, an anagram of Regina.
Jack of Clubs = Lancelot.