The Strength card, sometimes called Fortitude, depicts a calm woman holding open the mouth of a lion. This is one of the oldest cards, (being a Cardinal Virtue,) solidified at least by Pope Clement II’s death, (1047). (See Below). Crowley changed its formula to instead depict cosmic Lust symbolized by the Union of the Whore of Babalon & and the Beast. This is essentially the Thelemic version of Mother Nature and Father Sun.
Note in the Gnostic Mass the phrase, “Oh Lion and O Serpent that Destroyeth the Destroyer, be mighty among us.” Teth, the Hebrew letter attributed to this card, translates to “Serpent,” and it’s astrological attribution is Leo, the Lion. The Lust of their Union creates Art (i) & Life (A), destroying destruction with Strength.
In the Thoth Deck, the tail of the Lion is Chnoubis, a Lion/Serpent combo figure used by Gnostics: