In historical terms, to which Tarot relates, knights were appointed warriors and commanders in a special service to the monarch, kingdom and the people.
They were considered elite fighters receiving payment in the form of land and captured treasures, from which many leading, prominent, wealthy families had emerged forming the gentry, aristocratic circles, and finally the upper class.
Associated with the ideals of gallantry and chivalry, the Knights' code of conduct, allowed them to gain trust in the time of war as mercenaries skilled in battle on horseback, and in the time of peace appreciated as a participant in knights tournament, vivacious and colourful events.
Their actions and adventures were popularized in medieval literary cycles, especially in France, and as the legendary companions of King Arthur at the Round Table. The best-known orders were Knights Templars and the Teutonic Knights. The best-written novel about the post-chivalric period, Don Quixote, had a major influence on further literary work in The Three Musketeers by Alexandre Dumas, Adventures of Huckleberry Finn by Mark Twain, and Cyrano de Bergerac by Edmond Rostand.
Tarot depicts the classical knights in armour, the cavaliers holding their special prestige - a coin, a chalice, a sword, a wand. They are on a special mission to deliver or to defend, each accordingly to the suits they belong.
Knights are always in service. The nature of their service depends on whom they serve. Any Major Arcana or Court Card in a spread will be the lord over them. Surrounded only by Minor Arcana will suggest that the knight is not serving a high and mighty purpose, it's mission has been degraded to the common pursuit - often of vanity, low desires, immature, hasty action.
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Practise
Chariot card of Major Arcana represents all of the meaning and force behind the Knights. Place your cards in below order and contemplate the visuals, the interrelations, the insight you get.
It is quite a magnificent order. Each of the Knights has different armour as they serve a different purpose. Basically, we can state this is one Knight in its different roles:
Knight of Pentacles defends the material wealth, the treasury. He is not moving, he stands firmly on the ground and he will not let pass anybody without permission. He will only move if other cards accompany him. Then he will serve as a guardian of an armoured convoy protecting whatever is the treasure at hand. He wears black armour and sits on a black horse to make him invisible during the night, where robberies most likely occur.
Knight of Cups is a truly devoted cavalier straight from medieval romances. He delivers a chalice of love or of peace. He is on a mission to find his Dame, or as a representative of an enamoured lord. His chastity of intention is seen in the pure white background, his elegant armour and subtlety of his horse.
Knight of Swords is the one in a real battle, charging ahead, defending the kingdom. He is galloping on his horse at an immense speed; the clouds loos like smoke, so he may well have been summoned to take revenge.
Knight of Wands is on a tournament, jousting. Elaborate, colourful garment and his destrier are a perfect depiction of a gallant game ought to bring excitement, merriment and competitive spirit to the onlookers.
Change of Knights Character
Replace the Chariot Card with the Death Card. See how the scenery and meaning have changed.
Knight of Pentacles seems to be now in a funeral cortege. Riding with distinction, paying respect, representing the lords honours. Anyway, he is on a grave serious mission now. If there will be other malefic cards around, or the card reversed he may turn into a robber himself.
Knight of Cups bright look is dimmed by the Death presence yet he still remains pure in his character. The love he cherished may have disappeared but he will find solace in his ideals, as he understands the cycles of time. He may become stiffer on his horseback but will not give up his mission. He will spread love and peace, nevertheless.
Knight of Swords with Death companion is a killer. He won't stand back from the most transformative tasks, he will fly to the end. You can rely on that unless he brings the relevant and necessary transformation. And this is quite good - the bad thing ends definitely. There is definitely about this pair.
Knight of Wands is riding straight into Death arms. He has been unaware, ill-prepared and his tournament ends, not necessarily in death, but there his career seem to end, definitely.
Let's take another card with the horse in the scene, the Sun.
What a change!
Knight of Pentacles is so much more brightened up by the Sun's radiance. Still very responsible and protective of this vibrant energy - whatever may lay behind it. The celebration is here and he will see to it, making sure that everything goes according to a plan.
Knight of Cups is on a mission that will bring great joys and success.
Knight of Swords is charging not with revenge now but with glorious glory, in an upsurge of joy, vigorous enlightenment. He is literally spreading the enthusiasm around.
Knight of Wands seems to be the best match for the Sun, they almost run in each other arms. This may depict the best of fatherhood or simply joy of winning a big deal.