Strength is a Major Arcana and cardinal virtue in traditional Tarot, and is numbered either XI or VIII, depending on the deck. Historically it was called Fortitude, and in the Thoth Tarot deck it is called Lust.

History

Strength is traditionally the eleventh card and Justice the eighth, but the influential Rider-Waite-Smith deck switched the position of these two cards in order to make them a better fit with the astrological correspondences worked out by the Hermetic Order of the Golden Dawn, under which the eighth card is associated with Leo and the eleventh with Libra. Today many decks use this numbering, particularly in the English-speaking world.

Iconography

The design of this card is fairly constant across tarot decks. The key characters are that of a woman and a lion, with the woman looking calm and gentle, yet dominant over the lion. Many cards, including that of the Rider-Waite-Smith deck, have the woman clasping the lion’s jaws. Another feature of the RWS deck is a lemniscate (a kind of geometric form) hovering over the woman’s head. Other decks have the woman sitting upon the lion, or merely with one hand upon it. Some decks feature just one of the characters; flowers are often presented on this card.

Interpretation

The Chariot controls through mastery and authority. Card 8 is more subtle, even loving. Notice how the lion (itself a symbol of strength) is being guided and tamed by the woman’s gentle hands. Where the Chariot represented outer strength and will, the card of Strength represents inner power, the power of the human spirit to overcome any obstacle. This card means triumph of love over hate. Higher nature triumphs over material desire. This card makes it clear that we cannot aim to hide our instinctual nature behind pallid virtue but should open ourselves much more to encountering the living, sometimes terrifying archaic powers existing in each of us, in order to gradually tame them through loving acceptance and gentle force.

Symbolism

The Strength cards represents the control over material forces. The lion is a symbol of the fire within or the kundalini force that sits coiled within us at the base of the spine. The woman is symbolic of the subconscious, which controls vital functions without the need of conscious thought. She controls the lion with a gentle spiritual touch rather than from brute force.
In the Crowley deck this card is entitled Lust, and receives a different focus, as a sun sign (zodiac), namely Leo, implying a potency that is sexual, creative, and intuitive, which are all attributes of the element Fire. The other Leonine quality of generosity, or mercy, is also an aspect of this power or strength. There is a further connection with the heart chakra in kundalini yoga.
Cybele is associated with large cats, and is often depicted either enthroned with one or two flanking her, or in a chariot being pulled by large cats. Some contemporary sources have associated Cybele and Artemis with this card.
The Lion in the standard card represents the Sun, making Strength a solar hero, much like Hercules or Herakles, with whom lions are associated.

Associations

The sign associated with this card is Leo, the lion, of course. Strength is associated through the cross sum (the sum of the digits) with The Star. The Star is often interpreted as paradoxical and a bad omen. While the comet is associated with foretelling the birth of kings, the Star signaled to Dante that he had found his way out of the Underworld. Additionally, this card is associated with the suit of Wands.

Reading

When Strength appears in a throw, it may be a signal that The Querent is facing a challenge that requires a strong response, rather than brute force. Occasionally, strength comes by diverting forces, diverting rivers, or fighting on a new battleground.
It can be also a reminder not to despair or give up. You have the inner strength to endure and triumph. If you are pushing too hard, you need to withdraw for the moment and be patient. If other people or circumstances are driving you crazy, remember the strength that comes with love and forbearance. These will see you through the hardest moments.
This card also asks to tame the wild beast that lies within. Inside of each of us is a passionate and instinctual side which, depending on the person, will either burst out frequently or infrequently. If you are one of those people to act impulsively or irrationally, and blurt out angry comments or negative things to others, the Strength card calls on you to try to tame yourself. The woman in this card is calmly subduing the lion by offering peace, love, and warmth.

Strengh in the Tarot of Marseilles
Opposing cards

Chariot – hard control
Eight of Cups – weariness, lack of strength
Six of Swords – being listless, lacking heart
Five of Pentacles – ill-health, weakness

Reinforcing cards

Hanged Man – taking time, patience
Nine of Wands – stamina, strength to endu

Alternative decks

In the Vikings Tarot this card shows Thor trying to lift the Midgard Serpent, which he had been deceived into thinking was just a giant cat.
In the X/1999 Tarot version made by CLAMP, The Strength is Yuzuriha Nekoi and her Inugami, Inuki.
In the Mythic Tarot deck, Strength is depicted by Hercules.

Quote

In the midst of a green plain, surrounded by blue hills, I saw a woman with a lion. Girdled with wreaths of roses, a symbol of infinity over her head, the woman calmly and confidently covered the lion’s mouth and the lion obediently licked her hand.
“This is a picture of power”, said the voice. “It has different meanings. First it shows the power of love. Love alone can conquer wrath. Hatred feeds hatred. Remember what Zarathustra said: “Let man be freed from vengeance; this is a bridge for me which leads to higher hope and a rainbow in heaven after long storms”.
“Then it shows power of unity. These wreaths of roses suggest a magic chain. Unity of desires, unity of aspirations creates such power that every wild, uncontrolled, unconscious force is subdued. Even two desires, if united, are able to conquer almost the whole world.
“The picture also shows the power of infinity, that sphere of mysteries. For a consciousness that perceives the symbol of infinity above it, knows no obstacles and cannot be withstood”. The Symbolism of the Tarot by P D. Ouspensky (1913)