General Book of the Tarot, by A. E. Thierens, [1930], at sacred-texts.com
TRADITION: A man of the law or robe, councillor, senator, business-man, doctor, etc. "Whatsoever arises out of the idea of judgment and all its concessions, power, authority, command, militant intelligence . . ." (W.) Reversed: Bad intentions, evil, perversity, perfidy, cruelty, etc.
THEORY: The King of the suit of Earth, coming on the house of Aries, First house or ascendant. Whatsoever we may say of the 'reversed' side or weaker cases of this card, a king is a king and always denotes a higher accord, some one or something of principal value and rank. The king of the Martian and Saturnian element naturally is the king of matter and of war, i.e. also he who wins war and conducts the battle of earthy interests. It denotes the dominion and rulership of this element, consequently the military chief. This by the way we are astonished not to find mentioned by tradition, which mentions the man of the law, lawyer, advocate or judge, who rules or guides worldly strife and contention. As the ruler of the ascendant, the card may certainly mean any person heading a cycle of material activity and before all a pioneer on this plane, an independent man living on his own means. While material integrity is implicit, duplicity, doubt, double-dealing or uncertainty are definitely excluded. It indicates material certainty and severity, whether benefic or malific from a personal point of view, healthy or rude, even cruel. But we fail to see what it has to do with perversity, unless the meaning be the overruling of everything else, the higher by the material power, and the misuse of the latter. The card means an emphatic Yes.
CONCLUSION: General, captain, military chief, worldly authority, chief or captain in any branch of activity, man of the law; power, command, decision, initiative, pioneering, valour, integrity, severity, material certainty; in weak cases cruelty, misuse of power, tyranny.