In Roman legend, who removed a thorn from a lion's paw and was later spared by the same lion when forced to fight in the arena?

Androcles or Androclus is the name given by some sources to the main character of a common folktale. The story reappeared in the Middle Ages as "The Shepherd and the Lion" and was then ascribed to Aesop's Fables.

Androcles is given the Latin name of Androclus, a runaway slave of a former Roman consul administering a part of Africa. He takes shelter in a cave, which turns out to be the den of a wounded lion, from whose paw he removes a large thorn. In gratitude, the lion becomes tame towards him and henceforward shares his catch with the slave.

After three years, Androclus craves a return to civilization but is soon imprisoned as a fugitive slave and sent to Rome. There he is condemned to be devoured by wild animals in the Circus Maximus in the presence of an emperor who is named in the account as Gaius Caesar, presumably Caligula. The most imposing of the beasts turns out to be the same lion, which again displays its affection toward Androclus. After questioning him, the emperor pardons the slave in recognition of this testimony to the power of friendship, and he is left in possession of the lion.