androcles

n. legendary Roman slave who was forced to fight a lion but was saved by the lion that recognized and remembered Androcles as the one who in the past removed a thorn from its paw

Androcles (or Androclus), is a character, not definitively fictional, in tales that describe him as a slave in the Roman Empire in the early 1st century CE, about the time of Tiberius but possibly in the reign of Caligula.
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n. Androcles, legendary Roman slave who was forced to fight a lion but was saved by the lion, that recognized and remembered Androcles as the one who in the past removed a thorn from its paw