What is the origin of the idiom "the lion's share" and when to use it?

The idiom "the lion's share" has its origins in Aesop's fables, particularly the fable of "The Lion's Share." Aesop was an ancient Greek storyteller and fabulist. In this fable, a lion and several other animals hunted together and made a kill. The lion claimed the largest portion of the prey, justifying it by saying that he was the leader and the others owed him obedience. This idiomatic expression is used to refer to the largest or most significant portion of something, often in the context of dividing resources, responsibilities, or rewards.