The King of Diamonds
Also known as King of Coins, he is presumably Julius Caesar, a famous Roman dictator who reigned from October 49 BC to March 15 44 BC. He was assassinated by a group of senators led by his former known ally Marcus Brutus.
The King of Hearts
Also known as King of Cups, he is believed to represent King Charlemagne or Charles the Great who is regarded as the first Holy Roman Emperor and defeated the Saxons and the Bavarians making him a highly decorated warrior.
The King of Clubs
Also known as the King of Batons, many believe that this card is the conqueror Alexander the Great, king of Macedon. He is known to be an undefeated commander whose achievements are highly admired by Roman generals.
The King of Spades
Also known as King of Swords, he is said to be King David, a biblical king who killed the giant Goliath with a sling and became famously known as a righteous king.